Method and apparatus for converting data, method and apparatus for inverse converting data, and recording medium

ABSTRACT

A data converting apparatus includes a segmenting unit for setting a predetermined access unit, as an access unit to be processed, out of input data containing at least one access unit containing a plurality of data components per pixel, and for segmenting the access unit to be processed into at least one block; an analyzing unit for generating a basis for converting an expression format of each of the plurality of data components by respectively setting, as at least one analysis block, at least one segmented block and for performing a main component analysis on the plurality of data components; and a converting unit for converting the expression format of each of the plurality of data components per pixel forming the block to be processed.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority from Japanese Patent ApplicationNo. JP 2005-049955 filed on Feb. 25, 2005, the disclosure of which ishereby incorporated by reference herein.

BACKGROUND OF THE INVENTION

The present invention relates to a method and apparatus for convertingdata, a method and apparatus for inverse converting data, a method andsystem for processing information, a recording medium, and a computerprogram. More specifically, the present invention relates to a methodand apparatus for converting data, a method and apparatus for inverseconverting data, a method and system for processing information, arecording medium, and a computer program for discouraging unauthorizedcopying using an analog video signal by substantially degrading thevideo data in second and subsequent encoding and decoding operations ina manner free from any inconveniences, such as an increase in circuitscale, involved.

FIG. 1 illustrates a known video display system. The video displaysystem includes a reproducing apparatus 1 and a display 2.

The reproducing apparatus 1 includes a decoder 11 and digital-to-analog(D/A) converter 12. The decoder 11 decodes encoded digital video signalreproduced from a recording medium such as an optical disk (not shown),and supplies a digital video signal Vdg0, obtained as a result, to theD/A converter 12. The D/A converter 12 converts the digital video signalVdg0 into an analog video signal Van, and outputs the analog videosignal Van to the outside. The analog video signal Van, output from thereproducing apparatus 1, is supplied to the display 2.

The display 2, composed of a cathode-ray tube (CRT) display, aliquid-crystal display (LCD), or the like, displays an imagecorresponding to the analog video signal Van supplied from thereproducing apparatus 1.

As shown in FIG. 1, a known encoding apparatus 3 includes ananalog-to-digital (A/D) converter 21, an encoder 22, and a recorder 23.Unauthorized copying can be performed using the analog video signal Vanoutput from the encoding apparatus 3 and the reproducing apparatus 1.

When the analog video signal Van output from the reproducing apparatus 1is input to the encoding apparatus 3, the A/D converter 21analog-to-digital converts the analog video signal Van, therebyoutputting the resulting digital video signal Vdg′ to the encoder 22.The encoder 22 encodes the digital video signal Vdg′, thereby outputtingthe resulting encoded digital video signal Vcd′ to the recorder 23. Therecorder 23 records the encoded digital video signal Vcd′ onto arecording medium such as an optical disk (not shown). Unauthorizedcopying can thus be performed.

Japanese Unexamined Patent Application Publication No. 2001-245270discloses one technique. In accordance with the disclosed technique, ananalog video signal Van, which is copyright protected, is scrambled orprevented from being output to control unauthorized copying using theanalog video signal Van.

In accordance with Japanese Unexamined Patent Application PublicationNo. 10-289522, a compression decoding unit in at least one of areproducing section and a recording section includes a noise informationgenerator. Noise information that cannot be identified by only a singlevideo reproduction process is embedded in a digital video signal.Copying operation itself is enabled. If a copying operation is repeatedby a plurality of times, an image is severely degraded, and the numberof copying cycles is thus limited in practice.

In accordance with the technique disclosed in Japanese Unexamined PatentApplication Publication No. 2001-245270, unauthorized copying iscontrolled because the analog video signal Van is scrambled or preventedfrom being output. On the other hand, a normal image cannot be displayedon the display 2, either.

In accordance with the technique disclosed in Japanese Unexamined PatentApplication Publication No. 10-289522, the reproducing section and/orthe recording section needs the noise information generator and acircuit for embedding noise information. Circuit scale is thusincreased.

More specifically, although unauthorized copying using the analog videosignal Van is prevented in accordance with the techniques disclosed inJapanese Unexamined Patent Application Publication Nos. 2001-245270 and10-289522, an appropriate image cannot be displayed on the display 2 andthe circuit scale is increased.

Japanese Unexamined Patent Application Publication No. 2004-289685assigned to the same assignee of the present invention proposes atechnique that controls unauthorized copying using the analog videosignal in a manner free from the problems that no correct images aredisplayed, and that the circuit scale is increased.

In accordance with the technique proposed in Japanese Unexamined PatentApplication Publication No. 2004-289685, a phase of a digital videosignal that is obtained by analog-to-digital converting an analog videosignal is shifted, and the phase-shifted digital video signal isencoded. Copying is made impossible without degrading the quality of animage, i.e., with the quality of the image maintained. Thus,unauthorized copying using the analog video signal is discouraged.

The technique proposed in Japanese Unexamined Patent ApplicationPublication No. 2004-289685 makes unauthorized copying difficult. In thecurrent environment where digital content is widely available, there isa need for a further technique for unauthorized copying prevention inaddition to the technique proposed in Japanese Unexamined PatentApplication Publication No. 2004-289685.

SUMMARY OF THE INVENTION

It is thus desired that unauthorized copying using an analog videosignal be prevented by severely degrading video data in second andsubsequent encoding and decoding operations in a manner free from noimage displaying and an increase in circuit scale.

A data converting apparatus of one embodiment of the present inventionincludes a segmentor operable to set a predetermined access unit, as anaccess unit to be processed, out of input data containing at least oneaccess unit containing a plurality of data components per pixel, and tosegment the predetermined access unit into at least one block; ananalyzer operable to generate, on a per analysis block basis, a basisfor converting an expression format of each of the plurality of datacomponents by respectively setting, as at least one analysis block, theat least one segmented block, and to perform a main component analysison the plurality of data components on a per at least one analysis blockbasis; and a converter operable to convert the expression format of eachof the plurality of data components per pixel forming the block to beprocessed, by successively setting, as at least one block to beprocessed, the at least one segmented block, and by using apredetermined one of at least one basis generated by the analyzer.

The data converting apparatus may further include an analog distortiongenerator operable to generate an analog distortion in the input data.

The converter may encode, on a per predetermined unit basis, a datagroup containing the plurality of data components per pixel in theconverted expression format in the block to be processed.

The data converting apparatus may further include a vectorizer operableto generate an N-dimensional first vector having values of N datacomponents (N is an integer equal to 1 or larger) as element valuesthereof per pixel, on every M pixels (M is an integer equal to 1 orlarger) in a block to be processed, by successively setting, as theblock to be processed on a one-by-one basis, the at least one segmentedblock. The analyzer may generate the basis of the block to be analyzedby performing the main component analysis on the M first vectorsgenerated by the vectorizer when the block to be analyzed becomes theblock to be processed.

Preferably, the converter respectively converts the M first vectors ofthe block to be processed, from among the first vectors represented by afirst coordinate system having each of the N data components as an axisthereof, into M second vectors represented by a second coordinate systemhaving, as an axis, the basis generated by the analyzer when the blockto be processed becomes the block to be analyzed.

The converter may encode, on a per predetermined unit basis, a datagroup containing the M second vectors in the block to be processed.

The plurality of data components may include first pixel datarepresenting a red luminance level of a corresponding pixel, secondpixel data representing a green luminance level of the correspondingpixel, and a third luminance level representing a blue luminance levelof the corresponding pixel.

A data converting method of another embodiment of the present inventionfor converting at least part of an expression format of input datacontaining at least one access unit containing a plurality of datacomponents per pixel, includes setting a predetermined access unit ofthe input data, as an access unit to be processed, and segmenting thepredetermined access unit into at least one block; generating, on a peranalysis block basis, a basis for converting an expression format ofeach of the plurality of data components by respectively setting, as atleast one analysis block, at least one segmented block, and performing amain component analysis on the plurality of data components on a per atleast one analysis block basis; and converting the expression format ofeach of the plurality of data components per pixel forming the block tobe processed by successively setting, as at least one block to beprocessed, the at least one segmented block, and by using apredetermined one of at least one basis generated in the analyzing step.

A recording medium of yet another embodiment of the present inventionstores a computer program for causing a computer to perform a dataconverting method of converting at least part of an expression format ofinput data containing at least one access unit containing a plurality ofdata components per pixel. The data converting method includes setting apredetermined access unit of the input data, as an access unit to beprocessed, and segmenting the predetermined access unit into at leastone block; generating, on a per analysis block basis, a basis forconverting an expression format of each of the plurality of datacomponents by respectively setting, as at least one analysis block, atleast one segmented block, and performing a main component analysis onthe plurality of data components on a per at least one analysis blockbasis; and converting the expression format of each of the plurality ofdata components per pixel forming the block to be processed bysuccessively setting, as at least one block to be processed, at leastone segmented block, and by using a predetermined one of at least onebasis generated in the analyzing step.

In accordance with embodiments of the present invention, the expressionformat of at least part of the input data containing at least one accessunit containing the plurality of data components per pixel is converted.More specifically, a predetermined access unit is set as an access unitto be processed out of input data containing at least one access unitcontaining a plurality of data components per pixel, and the access unitto be processed is segmented into at least one block. The at least oneblock is respectively set as at least one analysis block, and the maincomponent analysis is performed on the plurality of data components on aper at least one analysis block basis, and the basis for converting theexpression format of each of the plurality of data components is thusgenerated on a per analysis block basis. At least one segmented block issuccessively set as a block to be processed. Using a predetermined basisof at least one generated basis to be analyzed, the expression format ofthe plurality of data components per pixel forming the block to beprocessed is thus converted.

Another embodiment of the present invention relates to a data inverseconverting apparatus in a system in which a predetermined first accessunit is set as an access unit to be processed out of original datacontaining at least one first access unit containing a plurality of datacomponents per pixel, and the first access unit to be processed issegmented into at least one block. The at least one segmented block issuccessively set as at least one analysis block, a main componentanalysis is performed on each of the plurality of data components on aper at least one analysis block basis, and a basis for converting anexpression format of each of the plurality of data components isgenerated on a per analysis block basis. At least one segmented block issuccessively set as a block to be processed, the expression format ofeach of the plurality of data components per pixel forming the block tobe processed is converted using a predetermined one of at least onegenerated basis, a second access unit containing the plurality of datacomponents per pixel in the converted expression format is generated,and the data inverse converting apparatus receives input data containingthe basis being input as part of the input data, the basis being used togenerate the second access unit. The data inverse converting apparatusincludes a separator operable to separate the input data into the secondaccess unit and the basis; and an inverse converter operable to inverseconvert, using the separated basis, the expression format of theplurality of data components per pixel forming the separated secondaccess unit.

A further embodiment of the present invention relates to a data inverseconverting method of a data inverse converting apparatus in a system inwhich a predetermined first access unit is set as an access unit to beprocessed out of original data containing at least one first access unitcontaining a plurality of data components per pixel, and the firstaccess unit to be processed is segmented into at least one block. The atleast one segmented block is successively set as at least one analysisblock, a main component analysis is performed on each of the pluralityof data components on a per at least one analysis block basis, and abasis for converting an expression format of each of the plurality ofdata components is generated on a per analysis block basis. At least onesegmented block is successively set as a block to be processed, theexpression format of each of the plurality of data components per pixelforming the block to be processed is converted using a predetermined oneof at least one generated basis, a second access unit containing theplurality of data components per pixel in the converted expressionformat is generated, and the data inverse converting apparatus receivesinput data containing the basis being input as part of the input data,the basis being used to generate the second access unit. The datainverse converting method includes separating the input data into thesecond access unit and the basis; and inverse converting, using theseparated basis, the expression format of the plurality of datacomponents per pixel forming the separated second access unit.

A still further embodiment of the present invention relates to arecording medium storing a computer program for causing a computer toperform a data inverse converting method of a data inverse convertingapparatus in a system in which a predetermined first access unit is setas an access unit to be processed out of original data containing atleast one first access unit containing a plurality of data componentsper pixel, and the first access unit to be processed is segmented intoat least one block. The at least one segmented block is successively setas at least one analysis block, a main component analysis is performedon each of the plurality of data components on a per at least oneanalysis block basis, and a basis for converting an expression format ofeach of the plurality of data components is generated on a per analysisblock basis. The at least one segmented block is successively set as ablock to be processed, the expression format of each of the plurality ofdata components per pixel forming the block to be processed is convertedusing a predetermined one of at least one generated basis, a secondaccess unit containing the plurality of data components per pixel in theconverted expression format is generated, and the data inverseconverting apparatus receives input data containing the basis beinginput as part of the input data, the basis being used to generate thesecond access unit. The data inverse converting method includesseparating the input data into the second access unit and the basis; andinverse converting, using the separated basis, the expression format ofthe plurality of data components per pixel forming the separated secondaccess unit.

In accordance with embodiments of the present invention, thepredetermined access unit is set as an access unit to be processed outof the original data containing at least one access unit containing theplurality of data components per pixel, and the access unit to beprocessed is segmented into at least one block. The at least onesegmented block is successively set as at least one analysis block, andthe main component analysis is performed on each of the plurality ofdata components on a per at least one analysis block basis. The basisfor converting the expression format of each of the plurality of datacomponents is generated on a per analysis block basis. The at least onesegmented block is successively set as a block to be processed, and theexpression format of each of the plurality of data components per pixelforming the block to be processed is converted using a predetermined oneof at least one generated basis. As a result, the second access unitcomposed of the plurality of data components per pixel in the convertedexpression format is generated. The input data containing the basisinput as part of the input data is input, the basis being used togenerate the second access unit. The input data is separated into thesecond access unit and the basis associated with the second access unit.At least one unit of encoded data separated from the input data is setas one unit of encoded data to be processed, and the one unit of encodeddata is decoded. The expression format of the plurality of datacomponents per pixel forming the separated second access unit is inverseconverted using the basis separated from the input data.

Another embodiment of the present invention relates to a data inverseconverting apparatus in a system in which a predetermined access unit isset as an access unit to be processed out of original data containing atleast one access unit containing a plurality of data components perpixel, and the access unit to be processed is segmented into at leastone block. The at least one segmented block is successively set as atleast one analysis block, a main component analysis is performed on eachof the plurality of data components on a per at least one analysis blockbasis, and a basis for converting an expression format of each of theplurality of data components is generated on a per analysis block basis.The at least one segmented block is successively set as a block to beprocessed, the expression format of each of the plurality of datacomponents per pixel forming the block to be processed is convertedusing a predetermined one of at least one generated basis, a data groupcontaining the plurality of data components per pixel in the convertedexpression format is encoded, at least one unit of encoded datarespectively corresponding to at least one block is obtained, and theinverse converting apparatus receives input data containing the basisbeing input as part of the input data, the basis being used to generateand being associated with the at least one unit of encoded data. Thedata inverse converting apparatus includes a separator operable toseparate the input data into the at least one unit of encoded data andthe basis associated with the at least one unit of encoded data; and aninverse converter operable to successively set the at least oneseparated unit of encoded data as a unit of encoded data to be processedone by one, to decode the unit of encoded data to be processed, and toinverse convert, using the basis associated with the unit of encodeddata to be processed from among the bases separated from the input data,the expression format of the plurality of data components per pixelforming the data group obtained as a result of decoding.

The original data may contain an analog distortion.

The at least one block is successively set one by one as a unit of blockto be processed, and N-dimensional first vectors having values of N datacomponents (N being an integer equal to 2 or larger) as component valuesper pixel are generated every M pixels (M being an integer equal to 1 orlarger) corresponding to the block to be processed. The basis of theblock to be analyzed is generated when the main component analysis isperformed on the M first vectors that are generated after the block tobe analyzed becomes the block to be processed. Each of the M firstvectors of the block to be processed, from among the first vectorsrepresented by a first coordinate system having as an axis each of the Ndata components, is converted into each of M second vectors representedby a second coordinate system having as an axis thereof the basisgenerated when the block to be processed becomes the block to beanalyzed, the data group containing the M second vectors is encoded on aper predetermined unit basis, and as a result, at least one unit ofencoded data corresponding to at least one block is obtained. Theinverse converter may decode one of encoded data to be processed, andrespectively inverse converts the M second vectors forming the datagroup obtained as a result of decoding the one of encoded data to beprocessed, into the M first vectors using the basis associated with theone unit of encoded data to be processed.

The plurality of data components may include first pixel datarepresenting a red luminance level of a corresponding pixel, secondpixel data representing a green luminance level of the correspondingpixel, and a third luminance level representing a blue luminance levelof the corresponding pixel.

Another embodiment of the present invention relates to a data inverseconverting method of a data inverse converting apparatus in a system inwhich a predetermined access unit is set as an access unit to beprocessed out of original data containing at least one access unitcontaining a plurality of data components per pixel, and the access unitto be processed is segmented into at least one block. The at least onesegmented block is successively set as at least one analysis block, amain component analysis is performed on each of the plurality of datacomponents on a per at least one analysis block basis, and a basis forconverting an expression format of each of the plurality of datacomponents is generated on a per analysis block basis. The at least onesegmented block is successively set as a block to be processed, theexpression format of each of the plurality of data components per pixelforming the block to be processed is converted using a predetermined oneof at least one generated basis, a data group containing the pluralityof data components per pixel in the converted expression format isencoded, at least one unit of encoded data respectively corresponding toat least one block is obtained, and the inverse converting apparatusreceives input data containing a basis being input as part of the inputdata, the basis being used to generate and being associated with atleast one unit of encoded data. The data inverse converting methodincludes separating the input data into at least one unit of encodeddata and the basis associated with the at least one unit of encodeddata; and successively setting the at least one separated unit ofencoded data as a unit of encoded data to be processed one by one,decoding the unit of encoded data to be processed, and inverseconverting, using the basis associated with the unit of encoded data tobe processed from among the bases separated from the input data, theexpression format of the plurality of data components per pixel formingthe data group obtained as a result of decoding.

Yet a further embodiment of the present invention relates to a recordingmedium storing a computer program for causing a computer to perform adata inverse converting method of a data inverse converting apparatus ina system in which a predetermined access unit is set as an access unitto be processed out of original data containing at least one access unitcontaining a plurality of data components per pixel, and the access unitto be processed is segmented into at least one block. The at least onesegmented block is successively set as at least one analysis block, amain component analysis is performed on each of the plurality of datacomponents on a per at least one analysis block basis, and a basis forconverting an expression format of each of the plurality of datacomponents is generated on a per analysis block basis. The at least onesegmented block is successively set as a block to be processed, theexpression format of each of the plurality of data components per pixelforming the block to be processed is converted using a predetermined oneof at least one generated basis, a data group containing the pluralityof data components per pixel in the converted expression format isencoded, at least one unit of encoded data respectively corresponding tothe at least one block is obtained, and the inverse converting apparatusreceives input data containing the basis being input as part of theinput data, the basis being used to generate and being associated withat least one unit of encoded data. The data inverse converting methodincludes separating the input data into at least one unit of encodeddata and the basis associated with the at least one unit of encodeddata; and successively setting at least one separated unit of encodeddata as a unit of encoded data to be processed one by one, decoding theunit of encoded data to be processed, and inverse converting, using thebasis associated with the unit of encoded data to be processed fromamong the bases separated from the input data, the expression format ofthe plurality of data components per pixel forming the data groupobtained as a result of decoding.

In accordance with embodiments of the present invention, thepredetermined access unit is set as an access unit to be processed outof the original data containing at least one access unit containing theplurality of data components per pixel, and the access unit to beprocessed is segmented into at least one block. The at least onesegmented block is successively set as at least one analysis block, andthe main component analysis is performed on each of the plurality ofdata components on a per at least one analysis block basis. The basisfor converting the expression format of each of the plurality of datacomponents is generated on a per analysis block basis, at least onesegmented block is successively set as one block to be processed, andthe expression format of each of the plurality of data components perpixel forming the block to be processed is converted using apredetermined one of at least one generated basis. As a result, at leastone unit of encoded data corresponding to at least one block isobtained. The input data containing the basis, which is used to generateand associated with at least one unit of encoded data, is input. Theinput data is separated into at least one unit of encoded data and thebasis associated with the at least one unit of encoded data. The atleast one unit of encoded data separated from the input data is set asone unit of encoded data to be processed, and the one unit of encodeddata is decoded. The expression format of the plurality of datacomponents per pixel forming the data group obtained as a result ofdecoding is inverse converted using the basis corresponding to the unitof encoded data from among the bases separated from the input data.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a known video display system;

FIG. 2 is a block diagram of a video processing system of one embodimentof the present invention;

FIG. 3 is a block diagram of an encoder of the video processing systemof FIG. 2;

FIG. 4 illustrates a process of a process area segmentor of FIG. 3;

FIG. 5 illustrates a process of a vectorizer of FIG. 3;

FIG. 6 illustrates the process of the vectorizer of FIG. 3;

FIG. 7 illustrates the process of the vectorizer of FIG. 3;

FIG. 8 illustrates the process of the vectorizer of FIG. 3;

FIG. 9 illustrates a process of an orthogonal transform basis generatorand an orthogonal transform encoder of FIG. 3;

FIG. 10 illustrates a process of the orthogonal transform basisgenerator and the orthogonal transform encoder of FIG. 3;

FIG. 11 illustrates a process of the orthogonal transform basisgenerator and the orthogonal transform encoder of FIG. 3;

FIG. 12 illustrates ADRC as one encoding technique applicable to theorthogonal transform encoder of FIG. 3;

FIG. 13 is a flowchart illustrating an encoding process of the encoderof FIG. 3;

FIG. 14 is a block diagram illustrating a decoder corresponding to theencoder of FIG. 3 in the video processing system of FIG. 2;

FIG. 15 illustrates a process of an inverse orthogonal transform encoderof FIG. 14;

FIG. 16 illustrates a process of a block decomposer of FIG. 14;

FIG. 17 is a flowchart illustrating a decoding process of the decoder ofFIG. 13;

FIG. 18 illustrates an example of a real image obtained through a firstcycle of encoding and decoding operations, namely, a real imagecorresponding to an analog video signal output from a reproducingapparatus;

FIG. 19 illustrates an example of a real image obtained through a secondcycle of encoding and decoding operations, namely, a real imagecorresponding to an encoded digital video signal output from the encoderof FIG. 3, recorded onto a recording medium by a recorder of FIG. 2, andthen reproduced from the recording medium;

FIG. 20 illustrates an image obtained through a first cycle of encodingand decoding operations, namely, an image corresponding to an analogvideo signal output from the reproducing apparatus;

FIG. 21 diagrammatically illustrates an image obtained through a firstcycle of encoding and decoding operations, namely, an imagecorresponding to a digital video signal output from the encoder of FIG.3, recorded onto a recording medium by the recorder of FIG. 2, and thenreproduced from the recording medium;

FIG. 22 is a functional block diagram illustrating the encoder of thevideo processing system of FIG. 2;

FIG. 23 is a flowchart illustrating an encoding process of the encoderin the functional structure of FIG. 22;

FIG. 24 is a functional block diagram illustrating the decodercorresponding to the encoder of FIG. 22 in the video processing systemof FIG. 2;

FIG. 25 is a flowchart illustrating a decoding process of the decoder ofFIG. 24;

FIG. 26 is a block diagram illustrating a video processing system of oneembodiment of the present invention different from the video processingsystem of FIG. 2; and

FIG. 27 is a block diagram of a hardware structure of part of anencoding section and a decoding section in accordance with oneembodiment of the present invention.

DETAILED DESCRIPTION

The embodiments of the present invention are described below withreference to the drawings. FIG. 2 illustrates a video processing systemof one embodiment of the present invention.

Referring to FIG. 2, elements identical to those discussed withreference to FIG. 1 are designated with the same reference numerals andthe discussion thereof is omitted as appropriate. An analog video signaloutput from a reproducing apparatus 1 is designated with Van in FIG. 1but the counterpart in FIG. 2 is designated with Van1. The referencesymbol Van1 is used to discriminate from Van2 output from a D/Aconverter 55.

As shown in FIG. 2, the video processing system includes the reproducingapparatus 1, a display 2, and a recording and encoding apparatus 31. Asystem including the known video processing system of FIG. 1 and therecording and encoding apparatus 31 added thereto constitutes the videoprocessing system of one embodiment of the present invention.

The analog video signal Van1 output from the reproducing apparatus 1contains an analog distortion. The analog distortion herein refers to adistortion that takes place in the signal when the signal isdigital-to-analog (D/A) converted. The analog distortion includes adistortion that takes place in a resulting analog signal when a digitalsignal is D/A converted into the analog signal by a D/A converter 12 inthe reproducing apparatus 1. More specifically, the analog distortionincludes a distortion that takes place in a signal when a high-frequencycomponent is removed from the signal, and a distortion that takes placein a signal when the signal is shifted in phase. Available as methods toevaluate image degradation due to the analog distortion are asignal-to-noise (S/N) evaluation method and a visual evaluation method(from the standpoint of visual degradation). The analog distortion maybe naturally or artificially generated (reference is made to an analogdistortion adder 451 of FIG. 26 to be discussed later).

As shown in FIG. 2, the recording and encoding, apparatus 31 includes anencoding section 41 and a decoding section 42. More specifically, theencoding section 41 is one example of an encoding apparatus as a dataconverting apparatus of one embodiment of the present invention, and thedecoding section 42 is one example of a decoding apparatus as a datainverse converting apparatus of one embodiment of the present invention.As shown in FIG. 2, the single recording and encoding apparatus 31includes the single encoding section 41 and the single decoding section42. Alternatively, the encoding section 41 is separately arranged fromthe decoding section 42 in the video processing system.

As shown in FIG. 2, the encoding section 41 includes an A/D converter51, an encoder 52, and a recorder 53.

The A/D converter 51 A/D converts the analog video signal Van1 outputfrom the reproducing apparatus 1 into a digital video signal Vdg1, andsupplies the digital video signal Vdg1 to the encoder 52. The encoder 52encodes the digital video signal Vdg1 into an encoded digital videosignal Vcd, and supplies the resulting encoded digital video signal Vcdto the recorder 53. The recorder 53 records the encoded digital videosignal Vcd onto a recording medium (not shown), such as an optical disk.

As shown in FIG. 2, the decoding section 42 includes a decoder 54, a D/Aconverter 55, and a display 56.

The decoder 54 decodes the encoded digital video signal Vcd output fromthe encoder 52 into a digital video signal vdg2, and supplies theresulting the digital video signal vdg2 to the D/A converter 55. The D/Aconverter 55 D/A converts the digital video signal vdg2 into an analogvideo signal Van2 and then supplies the resulting analog video signalVan2 to the display 56. The display 56, including a cathode-ray tube(CRT), a liquid-crystal display (LCD), or the like, displays an imagecorresponding to the analog video signal Van2 supplied from the D/Aconverter 55.

The digital video signal Vdg2 is obtained when the encoded digital videosignal Vcd output from the encoder 52 in the encoding section 41 of FIG.2 is decoded again by the decoder 54. The digital video signal Vdg2 isdifferent from a digital signal that is obtained when encoded digitalvideo signal Vcd′ output from the encoder 22 in the known encodingapparatus 3 of FIG. 1 is decoded again. The digital video signal Vdg2 issubstantially degraded from a digital video signal Vdg0 output from thedecoder 11 in the reproducing apparatus 1. In other words, the encoder52 performs an encoding process so that the digital video signal Vdg2obtained when the decoder 54 performs a decoding process issubstantially degraded from the digital video signal Vdg0 output fromthe decoder 11 in the reproducing apparatus 1.

An image resulting from reproducing the encoded digital video signal Vcdrecorded on the recording medium by the recorder 53 is substantiallydegraded from an image corresponding to analog video signal Van1 outputfrom the reproducing apparatus 1, namely, an image to be displayed onthe display 2. Each time the encoding process by the encoding section 41or an equivalent encoding unit and the decoding process by the decodingsection 42 or an equivalent decoding unit are repeated, the degree ofdegradation becomes severe. The encoding section 41 of FIG. 2 cannotperform a copying process with excellent image quality maintained.Unauthorized copying is thus prevented.

In the video processing system of FIG. 2, the recording and encodingapparatus 31 makes it difficult to perform a copying process withexcellent quality maintained. The analog video signal Van1 supplied fromthe reproducing apparatus 1 to the display 2 is free from anymanipulation. The image supplied to the display 2 is not degraded inimage quality. The video processing system of FIG. 2 overcomes theproblem associated with the technique disclosed in Japanese UnexaminedPatent Application Publication No. 2001-245270.

As shown in FIG. 2, the video processing system is free from mountingparticular circuits such as a noise information generator and a circuitrequired for embedding noise information. In other words, the videoprocessing system of FIG. 2 overcomes the problem associated with thetechnique disclosed in Japanese Unexamined Patent ApplicationPublication No. 10-289522.

The problems associated with the known techniques are thus overcome ifthe encoder 52 performs the encoding process so that the digital videosignal Vdg2 output in response to the decoding process of the decoder 54is substantially degraded in comparison with the digital video signalVdg0 output from the decoder 11 in the reproducing apparatus 1. Theencoder 52 simply performs the encoding process, and is not limited toany particular form. The encoder 52 may thus take any of a variety offorms. Along with any form taken by the encoder 52, the decoder 54 mayalso take a corresponding form.

Referring to FIGS. 3 through 21, the encoder 52 performing the encodingprocess involving a main component analysis and the decoder 54performing the respective decoding process are discussed in accordancewith embodiments of the present invention. The main component analysiswill be described later.

FIG. 3 illustrates the encoder 52 performing the encoding processinvolving the main component analysis. As shown in FIG. 3, the encoder52 includes an input unit 81 through an output unit 87.

The input unit 81 receives the digital video signal Vdg1 from the A/Dconverter 51, and supplies the digital video signal Vdg1 to the processarea segmentor 82.

The process area segmentor 82 segments the digital video signal Vdg1supplied from the input unit 81 into several blocks, and supplies thesegmented blocks to the vectorizer 83. The blocks segmented by theprocess area segmentor 82 are referred to process areas.

The process area (block) is not limited to any particular size. Smallblock to be discussed later is not limited to any particular size,either.

The vectorizer 83 extracts M units of process data, each represented inN dimensions, from the process area to be processed out of the processareas supplied from the process area segmentor 82, vectorizes each ofthe extracted M units of process data, and supplies the resultingN-dimensional M vectors (hereinafter referred to as a process vector) toeach of an orthogonal transform basis generator 84 and an orthogonaltransform encoder 85.

The orthogonal transform basis generator 84 generates an N N-dimensionalorthogonal bases by performing a main component analysis on the MN-dimensional vectors supplied from the vectorizer 83 on a per processarea basis, includes element values of N N-dimensional orthogonal bases,namely N×N element values, in a digital signal Vcdp, and supplies theresulting signal to each of the orthogonal transform encoder 85 and asuperimposer 86.

The orthogonal transform basis generator 84 performs the followingprocess in more detail.

The orthogonal transform basis generator 84 generates a matrix D having,as column elements, M N-dimensional process vectors supplied from thevectorizer 83, namely, the matrix D of N rows and M columns on a perprocess area basis. The orthogonal transform basis generator 84decomposes the matrix D into element matrices U, X, and V, eachsatisfying equation (1) by performing a singular value decomposition onthe matrix D:D=UΣV˜  (1)where the element matrix U represents a left singular matrix of N rowsand N columns, the element matrix V represents a right singular matrixof M rows and M columns, and the element matrix Σ represents a singularmatrix having N rows and M columns. V˜ represents the transpose of theelement matrix V.

Let r represent the rank of the matrix D (r is an integer equal to orsmaller than N), and each of the first r column elements of the elementmatrix U (left singular vector) is an orthogonal basis with the order ofimportance aligned from a left basis to a right basis. The first rcolumn elements from of the element matrix U (the left singular vector),namely, an f-th vector of the r orthogonal basis vectors from the right(f is an integer from 1 through r) is referred to as a f-th maincomponent. For simplicity of explanation, the rank of the matrix D is N.More specifically, N main components are obtained herein.

The orthogonal transform basis generator 84 includes the N×N elementvalues forming the element matrix U of equation (1), namely, N×Ncoefficients, in the digital signal Vcdp, and supplies the resultingdigital signal Vcdp to the orthogonal transform encoder 85 and thesuperimposer 86.

The orthogonal transform encoder 85 performs an axis transform processon each of the M N-dimensional process vectors supplied from theorthogonal transform basis generator 84 to convert the process area froma first coordinates system of the original N-dimension to a secondcoordinates system having N main components as an axis. More in detail,the orthogonal transform encoder 85 calculates equation (2):Va=U˜Vb  (2)where Vb represents a matrix having N rows and a single column (columnvector), and represents a predetermined one of the M N-dimensionalprocess vectors supplied from the vectorizer 83, namely, the processvectors represented in the first coordinates system, and Va is a matrixof N rows and a single column (column vector), namely, the processvector represented in the second coordinates system. U˜ represents thetranspose of the element matrix U of equation (1), namely, the transposeof the element matrix U having the N×N coefficients as element values inthe digital signal. Vcdp supplied from the orthogonal transform basisgenerator 84.

The orthogonal transform encoder 85 converts the M process vectors Vbinto the M process vectors Va on a per process area basis, respectively.

The orthogonal transform encoder 85 performs the encoding process, inaccordance with a predetermined encoding method, every M process vectorsVa of one process area subsequent to conversion, includes the processresult in the digital signal Vcdq and supplies the resulting signal tothe superimposer 86.

The “predetermined encoding method” does not refer to any particularencoding method but refers to a encoding method simply adopted from avariety of encoding methods by the orthogonal transform encoder 85. Theorthogonal transform encoder 85 can use any of a variety of encodingmethods.

The orthogonal transform encoder 85 extracts an element value at an f-throw of each of the M process vectors Va subsequent to conversion (f isan integer from 1 through N), and arranges extracted M element values aspixel values in a predetermined order. The orthogonal transform encoder85 thus generates a single digital video signal (block). The f-th rowelement value of the process vector Va (the element value at the f-throw from top in the column vector) refers to a coordinate value alongthe axis of the f main component (hereinafter f-th main componentvalue). The block refers to a signal video signal having, as pixelvalues, the f-th main component values of the M process vectors Vasubsequent to conversion. The block is hereinafter referred to as thef-th main component block.

The orthogonal transform encoder 85 generates N main component blocks,namely, a first main component block to N-th main component block.

The orthogonal transform encoder 85 quantizes each pixel value of themain component block to be processed (main component value) in each ofthe first main component block through the N-th main component block.For example, the following quantization methods can be adopted. In onequantization method, each pixel value forming a single main componentblock is divided by the same value in all of the first main componentblock through the N-th element block. In another quantization method,each pixel in a high-order main component block (meaning a smaller f ofthe f-th main component block) is divided by a value larger than a valueused in the division of a low-order main component block.

The orthogonal transform encoder 85 performs code assignment process,such as Huffman code, on each of the pixels subsequent to quantizationin each of the first main component block through the N-th maincomponent block, and includes the process result in the digital signalVcdq before supplying the resulting signal to the superimposer 86.

Alternatively, the orthogonal transform encoder 85 may perform theadaptive dynamic range coding (ADRC) process on each of the first maincomponent block through the N-th main component block, and may supply,to the superimposer 86, the digital signal Vcdq with the process resultcontained therewithin. The ADRC coding method will be described laterwith reference to FIG. 12.

The series of processes performed by the orthogonal transform encoder 85is referred to as an orthogonal transform encoding process. If theorthogonal transform encoding process is performed on one process area,the N orthogonal bases generated by the orthogonal transform basisgenerator 84 for the process area, namely, the N main componentsincluding the first main components through the N-th main components areused. The N main components including the first main components throughthe N-th main components for the one process area are collectivelyreferred to as a basis for orthogonal transform.

The digital signal Vcdq provided by the orthogonal transform encoder 85as a result of orthogonal transform encoding process is supplied to thesuperimposer 86. The superimposer 86 superimposes the digital signalVcdp (a group of coefficients representing the basis for orthogonaltransform every process area) supplied from the orthogonal transformbasis generator 84 onto the digital signal Vcdq supplied from theorthogonal transform encoder 85. The superimposer 86 then supplies aresulting digital signal as an encoded digital video signal Vcd to theoutput unit 87.

The output unit 87 outputs the encoded digital video signal Vcd to therecorder 53 and the decoder 54 of FIG. 2.

Referring to FIGS. 4 through 12, the process area segmentor 82 and theorthogonal transform encoder 85 in the encoder 52 of FIG. 2 are furtherdescribed below.

FIG. 4 illustrates the process result of the process area segmentor 82.More specifically, in accordance with the present embodiment, theprocess area segmentor 82 segments a video signal of one effectivescreen out of the digital video signal Vdg1 into process areas BL, eachhaving a size equal to 16 pixels in a horizontal direction and 16 pixelsin a vertical direction. A size having a h pixels in a horizontaldirection and having v pixel in a vertical direction (h×v) is referredto as a size of h×v pixels. As shown in FIG. 4, the process area BL hasa size of 16×16 pixels. Each blank circle represents pixel data forminga video signal of one effective screen area of the digital video signalVdg1. The same is true of FIGS. 5 and 6.

FIGS. 5 through 8 illustrate three examples of a vector generationmethod in which the vectorizer 83 generates the process vector Vb (referto equation (2)) using the process area BL.

A first vector generation method is described below.

In the first vector generation method, the vectorizer 83 furthersegments one process area BL into M small blocks. The vectorizer 83generates the process vector Vb by substituting a pixel value of N pixeldata units forming a small block to be processed for a predetermined oneof N elements in each of the segmented small N blocks. The substitutiondestination per pixel value is not limited to any particular one.

In accordance with the present embodiment, the process area BL having a16×16 pixel size is supplied from the process area segmentor 82 to thevectorizer 83. When the vectorizer 83 works in the first vectorgeneration method, the vectorizer 83 segments the process area BL havinga 16×16 pixel size into 16 small blocks BS, each having a 4×4 pixel sizeas shown in FIG. 5. In this case, N=M=16.

As shown in FIG. 6, the vectorizer 83 extracts pixel values of 16 pixeldata units forming the small block BS to be processed in an order ofcluster from top left one, and arranges the pixel values in the order ofextraction from top, thereby a process vector Vb (column vector) of16-th dimension.

As shown in FIG. 6, let Xk represent the value of k-th pixel data in thecluster order from top left (k is an integer from 1 through N, N=16 inthe case of FIG. 16) in the pixel data forming the small block BS. If itis not necessary to discriminate pixel data from the value thereof, thepixel data and the value thereof are collectively referred to as a pixelvalue. More specifically, the small block BS of FIG. 6 is composed of apixel value X1 through a pixel value X16. In this case, the vectorizer83 generates 16-dimensional process vector Vb (matrix Vb of 16 rows anda single column) represented by equation (3), and supplies the generatedprocess vector Vb to the orthogonal transform basis generator 84 and theorthogonal transform encoder 85:

$\begin{matrix}{{Vb} = \begin{bmatrix}{X\; 1} \\{X\; 2} \\\vdots \\{X\; 15} \\{X\; 16}\end{bmatrix}} & (3)\end{matrix}$

More specifically, the vectorizer 83 generates 16 16-dimensional processvectors Vb represented by equation (3), and supplies the generated 1616-dimensional process vectors Vb to the orthogonal transform basisgenerator 84 and the orthogonal transform encoder 85.

The orthogonal transform basis generator 84 generates the element matrixU of 16 rows and 16 columns in accordance with equation (1). Althoughequation (1) does not show, 16 column elements forming the elementmatrix U respectively represent the first main component through the16-th main component. In other words, the element matrix U representsthe basis of orthogonal transform for a single process area BL.

The orthogonal transform encoder 85 converts the 16 process vectors Vbrepresented by equation (3) (represented by the first coordinates systemhaving each pixel value as an axis) in one process area BL into theprocess vectors Va represented by the second coordinates system having,as axes, the first main component through the 16-th main component inaccordance with equation (2). More specifically, if the f-th maincomponent value is represented by Xf′, the 16 16-dimensional processvectors Vb represented by equation (3) are respectively converted into16 16-dimensional process vectors Va represented by the followingequation (4):

$\begin{matrix}{{Va} = \begin{bmatrix}{X\; 1^{\prime}} \\{X\; 2^{\prime}} \\\vdots \\{X\; 15^{\prime}} \\{X\; 16^{\prime}}\end{bmatrix}} & (4)\end{matrix}$

In this case, the orthogonal transform encoder 85 extracts the elementvalue Xf′ at the f-th row of the 16 process vectors Va subsequent toconversion represented by equation (4), namely, the f-th main componentvalue Xf′, and arranges the 16 extracted f-th main component values Xf′as pixel values in the order of arrangement of the small block BS ofFIG. 5, thereby generating the f-th main component block having a 4×4pixel size. The orthogonal transform encoder 85 thus generates the firstelement block through the 16-th element block, each having a 4×4 pixelsize. The orthogonal transform encoder 85 performs the encoding processin accordance with an appropriate encoding method on each of the firstelement block through the 16-th element block, includes the processresult in the digital signal Vcdq, and then supplies the resultingdigital signal Vcdq to the superimposer 86.

The first one of the three vector generation methods has been discussed.The second one of the three vector generation methods is describedbelow.

In the first vector generation method, only one type of pixel data(pixel value) is used for one pixel. In the second vector generationmethod, a plurality of types of video data (pixel values) is used forone pixel.

More specifically, digital video signals of a color image may becomponent signals including a signal representing a red luminance level(hereinafter referred to as R signal), a signal representing a greenluminance level (hereinafter referred to as G signal), and a signalrepresenting a blue luminance level (hereinafter referred to as Bsignal). The video data of one pixel forming the digital video signalincludes pixel data representing a red luminance value (hereinafterreferred to as R pixel value), pixel data representing a green luminancevalue (hereinafter referred to as G pixel value), and pixel datarepresenting a blue luminance value (hereinafter referred to as B pixelvalue).

In such a case, the second vector generation method is applicable.

In the second vector generation method, the vectorizer 83 segments oneprocess area BL into M small blocks. It should be here noted that eachunit of pixel data forming one small block extracted in the first vectorgeneration method is indicative of one pixel value (or considered to beindicative of one pixel value) while each unit of pixel data forming onesmall block extracted in the second vector generation method containsdata indicative of the R pixel value, the G pixel value, and the B pixelvalue.

The one small block BS of FIG. 6 is obtained in the first vectorgeneration method while three small blocks BSR, BSG, and BSB of FIG. 7are obtained in the second vector generation method. In other words, thesmall block BS of the color image is composed of three small blocks BSR,BSG, and BSB.

As shown in FIG. 7, the small block BSR is a small block having a 4×4pixel size composed of pixel data showing R pixel values only. The smallblock BSG is a small block having a 4×4 pixel size composed of pixeldata showing G pixel values only. The small block BSB is a small blockhaving a 4×4 pixel size composed of pixel data showing B pixel valuesonly. As shown in FIG. 7, a blank circle in the small block BSR denotespixel data meaning an R pixel value, a blank circle in the small blockBSG denotes pixel data meaning a G pixel value, and a blank circle inthe small block BSB denotes pixel data meaning a B pixel value.

As in the illustration of FIG. 7, the R pixel value at k-th pixel in theorder of cluster from top left in the R pixel data forming the smallblock BSR is represented by Xkr, the G pixel value at k-th pixel in theorder of cluster from top left in the G pixel data forming the smallblock BSG is represented by Xkg, and the B pixel value at k-th pixel inthe order of cluster from top left in the B pixel data forming the smallblock BSB is represented by Xkb. If there is no need for discriminatingpixel data from the pixel value thereof, the pixel data and the pixelvalue thereof are collectively referred to as a pixel value. In theexample of FIG. 7, the small block BSR is composed of R pixel value X1 rthrough R pixel value X16 r, the small block BSG is composed of G pixelvalue X1 g through G pixel value X16 g, and the small block BSB iscomposed of B pixel value X1 b through B pixel value X16 b.

The above discussion of FIG. 7 is also applied to FIG. 8.

In the second vector generation method, the vectorizer 83 handles thesmall blocks BSR, BSG, and BSB as a unit to be processed as show in FIG.7, and extracts 16 R pixel values X1 r through X16 r forming the smallblock BSR to be processed in the order of cluster from top left. Thevectorizer 83 extracts 16 G pixel values X1 g through X16 g forming thesmall block BSG to be processed in the order of cluster from top left,and extracts 16 B pixel values X1 b through X16 b forming the smallblock BSB to be processed in the order of cluster from top left. Thevectorizer 83 generates a 48-dimensional process vector Vb (columnvector).

More specifically, the vectorizer 83 generates the 48-dimensionalprocess vector Vb (of 48 rows and one column) represented by equation(5), and then supplies the resulting process vector Vb to the orthogonaltransform basis generator 84 and the orthogonal transform encoder 85:

$\begin{matrix}{{Vb} = \begin{bmatrix}{X\; 1r} \\\vdots \\{X\; 16r} \\{X\; 1g} \\\vdots \\{X\; 16g} \\{X\; 1b} \\\vdots \\{X\; 16b}\end{bmatrix}} & (5)\end{matrix}$

More specifically, the vectorizer 83 generates 16 48-dimensional processvectors Vb represented by equation (5) for each process area BLillustrated in FIG. 5, and supplies the 16 48-dimensional process vectorVb to the orthogonal transform basis generator 84 and the orthogonaltransform encoder 85.

In accordance with equation (1), the orthogonal transform basisgenerator 84 generates the element matrix U of 48 rows and 48 columns.Although not represented in equation (1), the 48-column elements formingthe element matrix U respectively represent the first main componentthrough the 48-th main component. More specifically, the element matrixU shows orthogonal basis of one process area BL.

The orthogonal transform encoder 85 converts the 16 process vectors Vbrepresented by equation (5) in one process area BL (represented by afirst coordinates system having, as axes thereof, the R pixel values,the G pixel values, and the B pixel values) into the process vectors Varepresented by a second coordinates system having, as axes thereof, thefirst main component through the 48-th main component in accordance withequation (2). More specifically, let Xf′ represent an f-th maincomponent, and the 16 48-dimensional process vectors Vb represented byequation (5) are converted into the 16 48-dimensional process vectors Varepresented by equation (6):

$\begin{matrix}{{Va} = \begin{bmatrix}{X\; 1^{\prime}} \\{X\; 2^{\prime}} \\\vdots \\{X\; 47^{\prime}} \\{X\; 48^{\prime}}\end{bmatrix}} & (6)\end{matrix}$

In this case, the orthogonal transform encoder 85 extracts the elementvalues Xf′ at the f-th row of the converted 16 process vectors Varepresented by equation (6), namely, the f-th main component values Xf′,and arranges the extracted 16 f-th main component values Xf′ asrespective pixel values in the small block BS of FIG. 5. The orthogonaltransform encoder 85 thus generates the f-th main component block of 4×4pixel size. For example, the orthogonal transform encoder 85 generatesthe first main component block through the 48-th main component block,each having a 4×4 pixel size. The orthogonal transform encoder 85performs the encoding process of an appropriate encoding method on eachof the first main component block through the 48-th main componentblock, includes the encoded blocks in the digital signal Vcdq, andsupplies the resulting digital signal Vcdq to the superimposer 86.

The first vector generation method and the second vector generationmethod have been discussed. The third vector generation method is nowdescribed.

In the third vector generation method, a plurality of types of pixeldata is used for one pixel. For each pixel, a process vector Vb isgenerated containing a plurality of types of pixel values.

For example, in the third vector generation method, an R pixel value, aG pixel value, and a B pixel value are arranged from top on a per pixelbasis to generate a process vector Vb (column vector). In other words,in the third vector generation method, the second vector generationmethod is applied to a small block having a size of a single pixel.

More specifically, the process area BL of 48×48 pixel size of FIG. 4 isnow supplied from the process area segmentor 82 to the vectorizer 83 ofFIG. 3. As shown in FIG. 8, the process area BL is composed of threelarge blocks BLR, BLG, and BLB.

As shown in FIG. 8, a large block BLR is a block containing 48×48 pixelshaving R pixel values only. The large block BLG is a block containing48×48 pixels having G pixel values only. The large block BLB is a blockcontaining 48×48 pixels having B pixel values only. In other words, thelarge block BLR is composed of R pixel values X1 r through X48 r, thelarge block BLG is composed G pixel values X1 g through X48 g, and thelarge block BLB is composed of B pixel values X1 b through X48 b.

In the third vector generation method, the vectorizer 83 extracts an Rpixel value Xkr, a G pixel value Xkg, and a B pixel value Xkb at k-thpixel in the order of cluster from top left from the process areas BLR,BLG, and BLB, each having a size of 48×48 pixels, and arranges the pixelvalues in the order of extraction, thereby generating athree-dimensional process vector Vb (column vector) represented byequation (7):

$\begin{matrix}{{Vb} = \begin{bmatrix}{Xkr} \\{Xkg} \\{Xkb}\end{bmatrix}} & (7)\end{matrix}$

More specifically, the vectorizer 83 generates 48 three-dimensionalprocess vectors Vb (equal to the number of pixels in the process areaBL) represented by equation (7) for one process area BL illustrated inFIG. 5 (a block group composed of three large blocks BLR, BLG, and BLGof FIG. 8), and supplies the generated process vectors Vb to theorthogonal transform basis generator 84 and the orthogonal transformencoder 85.

In accordance with equation (1), the orthogonal transform basisgenerator 84 generates the element matrix U of 3 rows and 3 columns. Inother words, an element matrix U represented by the following equation(8) is generated:

$\begin{matrix}{U = \begin{bmatrix}a_{00} & a_{10} & a_{20} \\a_{01} & a_{11} & a_{21} \\a_{02} & a_{12} & a_{22}\end{bmatrix}} & (8)\end{matrix}$

The three column elements forming the element matrix U represented byequation (8) represent a first main component through a third maincomponent. Let s represent the first element, t represent the secondelement, and u represent the third element, and the first through thirdelement are expressed by the following equations (9) through (11):

$\begin{matrix}{s = \begin{bmatrix}a_{00} \\a_{01} \\a_{02}\end{bmatrix}} & (9) \\{t = \begin{bmatrix}a_{10} \\a_{11} \\a_{12}\end{bmatrix}} & (10) \\{u = \begin{bmatrix}a_{20} \\a_{21} \\a_{22}\end{bmatrix}} & (11)\end{matrix}$

The orthogonal transform encoder 85 sets each of the 48 pixels formingone process area BL as a target pixel, and converts a process vector Vbof the target pixel represented by equation (8) (represented by thefirst coordinates system having, as axes, the R pixel value, the G pixelvalue, and the B pixel value) into a process vector Va of the targetpixel represented by the second coordinates system having, as axes, thefirst through third main components in accordance with equation (2). Thetranspose U˜ of the element matrix U of equation (2) is expressed in thefollowing equation (12):

$\begin{matrix}{U^{\sim} = \begin{bmatrix}a_{00} & a_{01} & a_{02} \\a_{10} & a_{11} & a_{12} \\a_{20} & a_{21} & a_{22}\end{bmatrix}} & (12)\end{matrix}$

When a k-th pixel in the order of cluster from top left in the processarea BL is a target pixel, the first main component value of the targetpixel is represented by Xks, the second main component value of thetarget pixel is represented by Xkt, and the third main component valueof the target pixel is represented by Xku. The process vector Vb of thetarget pixel represented by equation (7) is converted into the processvector Va of the target pixel represented by the following equation(13):

$\begin{matrix}{{Va} = \begin{bmatrix}{Xks} \\{Xkt} \\{Xku}\end{bmatrix}} & (13)\end{matrix}$

The process vector Vb represented by equation (17) is a vectorrepresented by the first coordinates system shown in the left portion ofFIG. 9. In the first coordinates system shown in the left portion ofFIG. 9, an axis r represents the axis of an r pixel value, an axis grepresents the axis of a g pixel value, and an axis b represents theaxis of a b pixel value. In contrast, the converted process vector Varepresented by equation (13) is a vector represented by the secondcoordinates system shown in the right portion of FIG. 9. In the secondcoordinates system shown in the right portion of FIG. 9, an axis of afirst main component s is the axis having, as a basis, the vectorrepresented by equation (9), an axis of a second main component t is theaxis having, as a basis, the vector represented by equation (10), and anaxis of a third main component u is the axis having, as a basis, thevector represented by equation (11).

If the k-th pixel in the order of cluster from top left in the processarea BL is a target pixel, the process vector Vb represented by equation(7) is one of expression format relating to a color of the target pixel,and relating to a point in space defined by the first coordinates systemillustrated in the left portion of FIG. 9. In contrast, the convertedprocess vector Va represented by equation (13) is another expressionformat relating to a color of the target pixel, and relating to a pointin another space defined by the second coordinates system illustrated inthe left portion of FIG. 9.

The main component analysis has been discussed in view of the equations.The main component analysis is now described from a different angle. IfM points are distributed in an N-dimensional space, a method ofgenerating orthogonal axes describing most efficiently the M points isthe main component analysis. The “orthogonal axes describing mostefficiently the M points” are the axes of the above-mentioned maincomponents.

From the above-mentioned standpoint, the main component analysis isperformed through the following first through fourth steps.

In the first step, position vectors at the M points distributed in theN-dimensional space are averaged, and then a difference vector betweeneach of the M points and the mean value thereof is calculated.

In the second step, a vector maximizing the sum of squares of the scalarproducts with the difference vectors is determined. The vectordetermined in the second step describes most appropriately the degree ofscatter of the M points distributed in the N-dimensional space. In otherwords, the vector determined in the second step is the above-mentionedfirst main component.

In the third step, from among the vectors orthogonalizing the first maincomponent, a vector maximizing the sum of the scalar products of thedifference vectors is determined as a second main component.

In the fourth step, the third step is iterated to determine a third maincomponent through N-th main component.

A color space (hereinafter referred to as RGB space) defined by thefirst coordinates system illustrated in the left portion of FIG. 9 ispresent as a “color space representing a color group of the 48 pixels inthe process area BL” of FIG. 4. When the main component analysis isperformed on the 48 points representing the colors of the 48 pixelsdistributed in the RGB space (the process vector Vb represented byequation (7)), a color space defined by the second coordinates systemillustrated in the right portion of FIG. 9 is determined as an optimumspace (optimum color space) from among the “color spaces representingthe color group of the 48 pixels in the process area BL” representingthe colors of the 48 pixels. The 48 points representing the colors ofthe 48 pixels distributed in the RGB space (the process vector Vbrepresented by equation (7)), namely, the 48 points as a result ofre-distributed in the optimum color space, are expressed by theconverted process vector Va represented by equation (13).

The process vector Vb generated in the first vector generation methodand defined by equation (3) has the following meaning. A first space(hereinafter small block space) having, as an axis, each of the pixelvalues X1 through X16 forming one small block BS is present as a “spacerepresenting 16 small blocks BS in the process area BL” of FIG. 5. Inthis case, 16 points distributed in the small block are represented bythe process vector Vb defined by equation (3). When the main componentanalysis is performed on the 16 points distributed in the small blockspace, an optimum space of the “spaces representing 16 small blocks inthe process area BL” (hereinafter after optimum small block) isdetermined as a space defined by the second coordinates system having,as axes, the first main component through the 16-th main component. The16 points distributed in the small space (the process vector Vb definedby equation (3)), namely, the 16 points-obtained as a result ofredistribution in the optimum small block, is represented by theconverted process vector Va defined by equation (4).

As described above, the orthogonal transform encoder 85 generates theconverted 48 process vectors Va defined by equation (13), namely, the 48process vectors Va re-expressed by the “color space representing thecolor group of the 48 pixels in the process area BL”.

The orthogonal transform encoder 85 generates a first main componentblock BLs, a second main component block BLt, and a third main componentblock BLu as shown in FIG. 10.

The orthogonal transform encoder 85 extracts element values Xks of the48 process vectors Vb at a first row, namely, first element values Xks,and arranges the extracted 48 first main component values Xks inlocations corresponding to the pixel positions of the process area BL ofFIG. 4 (at k-th position in the order of cluster from top left), therebygenerating the first main component block BLs having a size of 16×16pixels.

The orthogonal transform encoder 85 extracts element values Xkt of the48 process vectors Vb at a second row, namely, second element valuesXkt, and arranges the extracted 48 second main component values Xkt inlocations corresponding to the pixel positions of the process area BL ofFIG. 4 (at k-th position in the order of cluster from top left), therebygenerating the second main component block BLt having a size of 16×16pixels.

The orthogonal transform encoder 85 extracts element values Xku of the48 process vectors Vb at a third row, namely, third element values Xku,and arranges the extracted 48 third main component values Xku inlocations corresponding to the pixel positions of the process area BL ofFIG. 4 (at k-th position in the order of cluster from top left), therebygenerating the third main component block BLu having a size of 16×16pixels.

The orthogonal transform encoder 85 performs the encoding process of anappropriate encoding method on the first main component block BLs, thesecond main component block BLt, and the third main component block BLu,includes the encoded blocks in the digital signal Vcdq, and supplies theresulting digital signal to the superimposer 86. The encoding resultresponsive to the first main component block. BLs is referred to as afirst main component code, the encoding result responsive to the secondmain component block BLt is referred to as a second main component code,and the encoding result responsive to the third main component block BLuis referred to as a third main component code. The digital signals Vcdqof FIG. 11 (one process area BL), generated by the orthogonal transformencoder 85, are supplied to the superimposer 86.

The encoding method performed by the orthogonal transform encoder 85 isnot limited to any particular one. For example, the ADRC method may beused. As shown in FIG. 12, the ADRC method is outlined below.

The distribution of pixel values (signal levels) in a predeterminedblock is shown in the left portion of FIG. 12. As shown, the axisextending from left to right is a horizontal axis, the axis extendingupwardly and rightward at a slant angle is a vertical axis, and the axisextending upwardly is an axis of pixel value.

A graph illustrated in the right portion of FIG. 12 represents pixelvalues contained in the blocks illustrated in the left portion of FIG.12, arranged in the order of cluster in the horizontal direction or thevertical direction. In this graph, the axis extending from left to rightis the horizontal axis or the vertical axis, and the axis extendingupward is the axis of pixel value. Each blank circle represents onepixel. In each block of FIG. 12, pixel data of eight pixels (pixelvalues) is arranged in the horizontal direction or vertical direction.

The maximum one and the minimum one of the pixel values of the eightpixels consecutively arranged in the horizontal direction or thevertical direction are denoted by MAX and MIN, respectively. As shown inFIG. 12, dynamic range is defined by DR=MAX−MIN+1, and each pixel valueis re-quantized into the number of bits (1 bit in FIG. 12) smaller thanthe original number of bits (8 bits, for example). Such an encodingmethod is referred to as ADRC method.

More specifically, in the ADRC method for re-quantizing to 1 bit asshown in FIG. 12, the pixel value per pixel is compared with a thresholdvalue (bisectrix of the dynamic range in FIG. 12). If the pixel value isequal to or higher than the threshold value, a code “1” is assigned tothe pixel, and if the pixel value is lower than the threshold value, acode “0” is assigned to the pixel.

More specifically, in the right portion of FIG. 12, the values of thefirst through fourth pixels from the left side are above the thresholdvalue while the values of the fifth through eighth pixels are below thethreshold value. The values of the first through eighth pixels from theleft side are replaced with 1, 1, 1, 1, 0, 0, 0, and 0, respectively.The values of the ninth through twelfth pixels from the left side arebelow the threshold value while the values of thirteenth throughsixteenth pixels are above the threshold value. As shown in FIG. 12, thevalues of the ninth through sixteenth pixels are replaced with 0, 0, 0,0, 1, 1, 1, and 1, respectively.

It should be noted that the ADRC method allows a variable length code tobe output in response to a dynamic range, namely, that the number ofquantization bits is selected based on the magnitude of the dynamicrange. The smaller the dynamic range, the smaller number of bits is usedin re-quantization. With quantization distortion reduced, the redundancyof the pixel value is removed and the amount of data is minimized.

As shown in FIGS. 10 and 11, the orthogonal transform encoder 85performs the encoding process of the ADRC method on each of the firstmain component block BLs, the second main component block BLt, and thethird main component block BLu. Using the property of the ADRC method,the orthogonal transform encoder 85 can change the number ofquantization bits in each of the first main component block BLs, thesecond main component block BLt, and the third main component block BLu.More specifically, in the main component analysis, most power isconcentrated on the first main component, next most power applied on thesecond main component, and less power applied on the third maincomponent. The magnitudes of the dynamic ranges of the blocks are thefirst main component block BLs, the second main component block BLt, andthe third main component block BLu in the magnitude order from large tosmall. The orthogonal transform encoder 85 sets the number ofquantization bits of the first main block BLs to the largest (to 3 bits,for example), the number of quantization bits of the second main blockBLt to the second largest (to 2 bits, for example), and the number ofquantization bits of the third main block BLu to the smallest (to 1 bit,for example).

As previously described, the encoding method of the orthogonal transformencoder 85 is not limited to any particular one. However, since power isconcentrated on the first main component in the main component analysis,the use of an encoding method that permits information to remain in thefirst main component block BLs, more specifically, the use of the ADRCmethod, is more preferable.

The structure of the encoder 52 of FIG. 3 has been discussed. Theencoding process of the encoder 52 of FIG. 3 is discussed with referenceto a flowchart of FIG. 13.

In step S41, the input unit 81 inputs one frame of digital video signalVdg1, for example. When one frame digital video signal Vdg1 is suppliedfrom the input unit 81 to the process area segmentor 82, processingproceeds to step S42.

In step S42, the process area segmentor 82 segments the one frame ofdigital video signal Vdg1. More specifically, the one frame of digitalvideo signal Vdg1 is segmented into a plurality of process areas. Whenthe plurality of process areas in one frame is supplied from the processarea segmentor 82 to the vectorizer 83, processing proceeds to step S43.

In step S43, the vectorizer 83 extracts M units of process datarepresented N dimensions from a process area to be processed out of theprocess areas into which the one frame of digital video signal Vdg1 issegmented in step S42. The vectorizer 83 vectorizes the M units ofprocess data. Through the process in step S43, M process vectors Vb (seeequation (2)) are obtained per process area, and then supplied to theorthogonal transform basis generator 84 and the orthogonal transformencoder 85. Processing proceeds to step S44.

In step S44, the orthogonal transform basis generator 84 adaptivelygenerates the basis of orthogonal transform of the process area to beprocessed out of the process areas into which the one frame of digitalvideo signal Vdg1 is segmented in step S42, i.e., generates the firstmain component through the N-th main component. Through the process instep S44, the basis of orthogonal transform is obtained on a per processarea basis, and then included into the digital signal Vcdp. If theresulting digital signal Vcdp is the supplied to the orthogonaltransform encoder 85 and the superimposer 86, in other words, if the oneframe of digital signal Vcdp is supplied to the orthogonal transformencoder 85 and the superimposer 86, processing proceeds to step S45.

In step S45, the superimposer 86 performs the orthogonal transformencoding process on the M N-dimensional process vectors Vb for theprocess area to be processed, using the basis of orthogonal transform inthe process area to be processed, out of the process areas into whichthe one frame of digital video signal Vdg1 is segmented in step S42.

Through the process in step S45, the result of orthogonal transportencoding process of one frame is included in the digital signal Vcdq,and the resulting digital signal Vcdq is supplied from the orthogonaltransform encoder 85 to the superimposer 86. Processing proceeds to stepS46.

In step S46, the superimposer 86 generates the encoded digital videosignal Vcd by superimposing the one frame of digital signal Vcdp outputfrom the orthogonal transform basis generator 84 in step S44 onto theone frame of digital signal Vcdq output from the orthogonal transformencoder 85 in step S45.

When the encoded digital video signal Vcd is output from thesuperimposer 86 to the output unit 87, processing proceeds to step S47.In step S47, the output unit 87 outputs the encoded digital video signalVcd to the outside.

In step S48, the encoder 52 determines whether all frames to beprocessed have been processed.

If it is determined in step S48 that all frames have not been processed,in other words, if the answer to the determination in step S48 is no,processing returns to step S41 to repeat step S41 and subsequent steps.More specifically, a next one frame digital video signal Vdg1 of isinput in step S41, the above-referenced encoding process is performed insteps S42 through S46, and one frame of encoded digital video signal Vcdof is thus obtained as a result. The encoded digital video signal Vcd isoutput in step S47.

A loop process in steps S41 through S48 is performed to process allframes. When last frame of encoded digital video signal Vcd is output,the answer to the determination in step S48 is yes, and the encodingprocess of FIG. 13 is thus completed.

The encoding process of the encoder 52 of FIG. 3 has been discussed withreference to FIG. 13.

With reference to FIGS. 14 through 17, the decoder 54 of one embodimentof the present invention, corresponding to the encoder 52 of FIG. 3, isdescribed below.

FIG. 14 illustrates the decoder 54 corresponding to the encoder 52 ofFIG. 3. As shown in FIG. 14, the decoder 54 includes an input unit 101through an output unit 105.

Upon receipt of the encoded digital video signal Vcd output from theencoder 52 of FIG. 3, the input unit 101 supplies the encoded digitalvideo signal Vcd to the data decomposer 102.

The data decomposer 102 decomposes the encoded digital video signal Vcdinto the digital signal Vcdp output from the orthogonal transform basisgenerator 84 of FIG. 3 and the digital signal Vcdq output from theorthogonal transform encoder 85 of FIG. 3, and then supplies the digitalsignal Vcdp and the digital signal Vcdq to the inverse orthogonaltransform decoder 103.

The inverse orthogonal transform decoder 103 performs, on the digitalsignal Vcdq, a decoding process (inverse quantization process, etc.) ofthe encoding method adopted by the orthogonal transform encoder 85 ofFIG. 3. Through the decoding process, the first main component blockthrough the N-th main component block are obtained on a per process areabasis. More specifically, upon receipt of the digital signal Vcdq ofFIG. 11 from the data decomposer 102, the inverse orthogonal transformdecoder 103 generates (restores) the first main component block BLs, thesecond main component block BLt and the third main component block BLufrom the first main component code, the second main component code, andthe third main component code, respectively, as shown in FIG. 15.

The inverse orthogonal transform decoder 103 generates (restores), on aper process area basis, the M process vectors Va defined by equation(2), namely, the process vectors Va represented in the space defined bythe second coordinates system having, as the axes, the first maincomponent through the N-th main component, from the first main componentblock through the N-th main component block, each having a size of Npixels.

The inverse orthogonal transform decoder 103 performs, on a per processarea basis, an inverse axis transform process on each of the M processvectors Va to inverse transform the second coordinates system into thefirst coordinates system (having an pixel value as an axis). More indetail, the inverse orthogonal transform decoder 103 calculates equation(14), thereby generating (restoring) the M process vectors. Vb from theM process vectors Vb respectively on a per process area basis:Vb=(U˜)⁻¹ Va  (14)where (U˜)⁻¹ represents the inverse matrix of the transpose (U˜) of theelement matrix U defined by equation (1), and is a matrix having N×Ncoefficients contained, as element values, in the digital signal Vcdpsupplied from the data decomposer 102. The inverse orthogonal transformdecoder 103 can generate the matrix (U˜)⁻¹ using the digital signal Vcdpsupplied from the data decomposer 102.

The inverse orthogonal transform decoder 103 supplies the M processvectors Vb to the block decomposer 104 on a per process area basis.

A series of process steps of the inverse orthogonal transform decoder103 is referred to as an inverse orthogonal transform decoding process.

The block decomposer 104 generates (restores) each process area from theM process vectors Vb supplied from the inverse orthogonal transformdecoder 103 on a per process area basis, arranges each process area tothe former location thereof prior to segmentation, and outputs aresulting one frame digital video signal to the output unit 105 as oneframe digital video signal Vdg2, which is a decoded signal of theencoded digital video signal Vcd of one frame.

More specifically, the first main component block BLs, the second maincomponent block BLt and the third main component block BLu of FIG. 15are generated (stored) during the inverse orthogonal transform decodingprocess of the inverse orthogonal transform decoder 103. As shown inFIG. 16, the block decomposer 104 generates (restores) the process areaBL composed of the large block BLR (block composed of the R pixelvalues), the large block BLG (block composed of the G pixel values), andthe large block BLB (block composed of the B pixel values) as previouslydiscussed with reference to FIG. 8. The block decomposer 104 arranges aplurality of process areas BL in the locations prior to segmentation asillustrated in FIG. 4, thereby resulting in one frame digital videosignal Vdg2. The resulting digital video signal Vdg2 is supplied fromthe block decomposer 104 to the output unit 105.

The output unit 105 outputs the digital video signal Vdg2 to the D/Aconverter 55 of FIG. 2.

The structure of the decoder 54 of FIG. 14 has been discussed. Thedecoding process of the decoder 54 of FIG. 14 is described below withreference to a flowchart of FIG. 17.

In step S61, the input unit 101 receives one frame of the encodeddigital video signal Vcd. When the one frame encoded digital videosignal Vcd is supplied from the input unit 101 to the data decomposer102, processing proceeds to step S62.

In step S62, the data decomposer 102 decomposes one frame of encodeddigital video signal Vcd into one frame of digital signal Vcdp and oneframe of digital signal Vcdq. When the one frame of digital signal Vcdpand the one frame of digital signal Vcdq are supplied to the inverseorthogonal transform decoder 103, processing proceeds to step S63.

In step S63, the inverse orthogonal transform decoder 103 performs theinverse orthogonal transform decoding process on the one of digitalsignal Vcdq using the one frame of digital signal Vcdp. When the processresult from step S63 is supplied to the block decomposer 104, processingproceeds to step S64.

In step S64, the block decomposer 104 generates one frame of digitalvideo signal Vdg2 using the process result in the inverse orthogonaltransform decoding process in step S63. When the digital video signalVdg2 is supplied from the block decomposer 104 to the output unit 105,processing proceeds to step S65.

In step S65, the output unit 105 outputs one frame of digital videosignal Vdg2 to the outside.

In step S66, the decoder 54 determines whether all frames to beprocessed have been processed.

If all frames have not been processed, namely, if the answer to thedetermination in step S66 is no, processing returns to step S61 torepeat step S61 and subsequent steps. More specifically, a next oneframe of encoded digital video signal Vcd is input in step S61, and thedecoding process discussed with reference to steps S62 through S64 isperformed. As a result, one frame of digital video signal Vdg2 isobtained and output in step S65.

Steps S61 through S66 are looped to process all frames. When last frameof digital video signal Vdg2 is output, the answer to the determinationin step S66 is yes. The decoding process of FIG. 17 is thus completed.

The decoding process of the decoder 54 of FIG. 14 has been describedwith reference to FIG. 17.

As described above, the analog video signal Van1 accompanied by ananalog distortion output from the reproducing apparatus 1 of FIG. 2 issupplied to the A/D converter 51 for A/D conversion, and is then outputto the decoding section 42 of FIG. 3 as the digital video signal Vdg1.

The encoder 52 of FIG. 3 segments the digital video signal Vdg1 into aplurality of process areas. The encoder 52 of FIG. 3 generates the MN-dimensional process vectors Vb (see equation (2)) from the processarea to be processed. The encoder 52 of FIG. 3 generates a basis oforthogonal transform adaptive to the process area to be processed, usingthe M process vectors Vb of the process area to be processed, for eachof the plurality of process areas. The encoder 52 of FIG. 3 performs theorthogonal transform encoding process on the process area to beprocessed, using the basis of orthogonal transform of the process areato be processed, for each of the plurality of process areas. The encoder52 of FIG. 3 outputs, as the encoded digital video signal Vcd, a digitalsignal composed of the digital signal Vcdq indicative of the result ofthe orthogonal transform encoding process and the digital signal Vcdqindicative of the basis of the corresponding orthogonal transform.

The encoded digital video signal Vcd output from the recorder 53 of FIG.3 is supplied to the recorder 53 of FIG. 2. The recorder 53 records theencoded digital video signal Vcd onto a recording medium such as anoptical disk. The recorder 53 thus performs a copying process inresponse to the analog video signal Van1.

If the analog video signal Van1 output from the reproducing apparatus 1is a signal that has undergone a first encoding and decoding operation,the encoded digital video signal Vcd recorded on the recording medium bythe recorder 53 becomes a signal that has undergone a second encodingand decoding operation. A digital video signal as a result of decodingby another apparatus (not shown) having the decoder 54 of FIG. 14 alsobecomes a signal that has undergone a second encoding and decodingoperation. The digital video signal that has undergone a second encodingand decoding operation is substantially degraded in comparison with thedigital video signal Vdg0 output from the decoder 11 in the reproducingapparatus 1.

This is because the analog video signal Van1 is accompanied by theanalog distortion as described above.

More specifically, if the analog video signal Van1 is accompanied by theanalog distortion due to signal phase shifting, fluctuations take placein a sampling phase when the A/D converter 51 converts the analog videosignal Van1 into a digital signal. The phase fluctuations cause theplurality of process areas, into which the encoder 52 has segmented thedigital video signal Vdg1, to shift in position with respect to theposition thereof in the first encoding and decoding process.

Because of this, the encoder 52 of FIG. 3 generates a basis oforthogonal transform (each main component) different from the basis oforthogonal transform used in the first encoding in each of the pluralityof process areas. Since the orthogonal transform encoding process isperformed on the process vector Vb in the process area to be processed,using the orthogonal transform basis in the process area to beprocessed, a new quantization distortion different from a quantizationdistortion that took place in the first encoding operation is furthergenerated, thereby becoming a large distortion.

The encoded digital video signal Vcd output from the encoder 52 of FIG.3, recorded on the recording medium by the recorder 53 of FIG. 2, andthen reproduced from the recording medium becomes a substantiallydegraded image in comparison with an image corresponding to the analogvideo signal Van1 output from the reproducing apparatus 1, namely, animage displayed on the display 2.

FIGS. 18 and 19 illustrate the encoding method in accordance with thethird vector generation method, namely, the encoding method in which themain component analysis is performed on the colors per pixel (the Rpixel value, the G pixel value, and the B pixel value). FIG. 18illustrates a real image obtained through a first encoding and decodingoperation, i.e., a real image corresponding to the analog video signalVan1 output from the reproducing apparatus 1. In contrast, FIG. 19illustrates a real image obtained through a second encoding and decodingoperation, i.e., a real image that is obtained by reproducing theencoded digital video signal Vcd from the recording medium after theencoded digital video signal Vcd is output from the decoding section 42of FIG. 3 and then recorded on the recording medium by the recorder 53of FIG. 2.

FIGS. 18 and 19 illustrate portions of images in enlargement. Each imageis a black and white image converted from an original color image. Asshown in FIGS. 18 and 19, graphs in the left portions thereof are plotsof the R pixel value, the G pixel value, and the B pixel value of pixelsconsecutively arranged as shown by arrow-headed lines on the rightportion of FIGS. 18 and 19. In each graph, the abscissa represents thepixel position along the arrow-headed line, and the ordinate representsthe pixel value (luminance level). Waveform R represents a waveform ofthe R pixel value, waveform G represents a waveform of the G pixelvalue, and waveform B represents a waveform of the B pixel value. Asshown in FIG. 18, Xbr, Xbg, and Xbb represent the R pixel value, the Gpixel value, and the B pixel value of a pixel gb, respectively. As shownin FIG. 19, Xar, Xag, and Xab represent the R pixel value, the G pixelvalue, and the B pixel value of a pixel ga at the same location as thepixel gb of FIG. 18.

In comparison of FIGS. 18 and 19, pixels surrounding the pixel gb, beingblank in FIG. 18 become ones suffering from block distortion with colorshifting surrounding the pixel ga in FIG. 19 after the second encodingand decoding operation.

FIGS. 20 and 21 illustrate the encoding method for the third vectorgeneration method, namely, the encoding method in which the maincomponent analysis is performed on the colors per pixel (the R pixelvalue, the G pixel value, and the B pixel value). FIG. 20 illustrates areal image obtained through a first encoding and decoding operation,i.e., a real image corresponding to the analog video signal Van1 outputfrom the reproducing apparatus 1. In contrast, FIG. 21 illustrates areal image obtained through a second encoding and decoding operation,i.e., a real image that is obtained by reproducing the encoded digitalvideo signal Vcd from the recording medium after the encoded digitalvideo signal Vcd is output from the decoding section 42 of FIG. 3 andthen recorded on the recording medium by the recorder 53 of FIG. 2.

FIGS. 20 and 21 illustrate portions of images in enlargement. Each imageis a black and white image converted from an original color image. Asshown in FIG. 20, a process area BL1 used in a first encoding operationis denoted by a broken-lined square. As shown in FIG. 21, a process areaBL2 used in a second encoding operation is denoted by a solid-linedsquare.

In comparison of FIGS. 20 and 21, each process area BL1 is optimized inFIG. 20. In contrast, as shown in FIG. 21, a block is mixed with ablock, optimized through the first encoding (i.e., the blockcorresponding to the process area BL1), due to phase shifting throughthe second encoding, and used as process area BL2. As a result, blockcolor shifting occurs, thereby leading to a visibly unfavorable image.

If the analog video signal Van1 output from the reproducing apparatus 1has undergone a second or further encoding and decoding operations, adigital video signal encoded by the encoder 52 of FIG. 3 and decodedbecomes a signal that has undergone a third or further encoding anddecoding operation. The resulting image becomes further degraded.

If the encoded digital video signal having undergone the third orfurther encoding and decoding operation is recorded onto the recordingmedium by the recorder 53, and then reproduced, a resulting imagebecomes a more significantly degraded image in comparison with the imagecorresponding to the analog video signal Van1 output from thereproducing apparatus 1, i.e., the image displayed on the display 2. Theencoding section 41 cannot copy images with excellent image qualitymaintained. Unauthorized copy is thus discouraged.

For the same reason, in the decoding section 42 having the decoder 54 ofFIG. 14, an image displayed on the display 56, i.e., an imagecorresponding to the analog video signal Van2 output from the D/Aconverter 55 is significantly degraded in comparison with the imagecorresponding to the analog video signal Van1 output from thereproducing apparatus 1, namely, the image displayed on the display 2.The degree of degradation becomes severe as the encoding and decodingprocess is repeated.

In the video processing system including the encoder 52 of FIG. 3 andthe decoder 54 of FIG. 14, the recording and encoding apparatus 31including the encoder 52 of FIG. 3 and the decoder 54 of FIG. 14performs a process to make it difficult to perform a copying processwith excellent image quality maintained. No particular manipulation isperformed on the analog video signal Van1 supplied from the reproducingapparatus 1 to the display 2. As a result, the image quality of theimage displayed on the display 2 is free from any degradation. Morespecifically, the video processing system including the encoder 52 ofFIG. 3 and the decoder 54 of FIG. 14 overcomes the problem presented bythe technique disclosed in Japanese Unexamined Patent ApplicationPublication No. 2001-24527.

As shown in FIGS. 3 and 14, the video processing system including theencoder 52 and the decoder 54 is free from the need to include anyparticular circuits such as a noise information generator and a circuitfor embedding noise information, and from any increase in circuit scale.More specifically, the video processing system of FIG. 2 including theencoder 52 of FIG. 3 and the decoder 54 of FIG. 14 overcomes the problempresented by the technique disclosed in Japanese Unexamined PatentApplication Publication No. 10-289522.

If the analog video signal Van1 contains no analog distortion, a processarea at the same position as a previous cycle is used in a second andsubsequent encoding cycle. As a result, the orthogonal transform basis(main component) generated in the preceding encoding cycle remainsalmost unchanged in the second and subsequent encoding cycle. Thequantization distortion in the second and subsequent encoding cycles isextremely small, and reproduction is performed at normal quality level.

The encoder 52 and the decoder 54 of FIG. 2 in accordance with theembodiment of the present invention have been discussed with referenceto FIGS. 3 through 21.

The encoder 52 of FIG. 2 is not limited to the structure discussed withreference to FIG. 3, and may take any of a variety of forms. The decoder54 of FIG. 2 is not limited to the structure discussed with reference toFIG. 14, and may take any of a variety of forms.

It is sufficient if the encoder 52 of FIG. 2 has a functional structureshown in FIG. 22. The present invention is not limited to any ofembodiments that embody the functional structure of FIG. 22. The encoder52 of FIG. 3 is one of the variety of embodiments. FIG. 22 illustrates ageneral functional structure of the encoder 52 of FIG. 2 (comprehensiveconcept of the example of FIG. 3). FIG. 23 is a flowchart of theencoding process of the encoder 52 having the functional structure ofFIG. 22.

Similarly, it is sufficient if the decoder 54 of FIG. 2 has a functionalstructure of FIG. 24. The present invention is not limited to any ofembodiments that embody the functional structure of FIG. 24. The decoder54 of FIG. 14 is one of a variety of embodiments that embody thefunctional structure of FIG. 24. FIG. 24 illustrates a generalfunctional structure of the decoder 54 of FIG. 2 (comprehensive conceptof the example of FIG. 14). FIG. 25 is a flowchart of the decodingprocess of the decoder 54 having the functional structure of FIG. 23.

The encoder 52 and the decoder 54 of FIG. 2 are described below withreference to FIGS. 22 through 24.

As shown in FIG. 22, the encoder 52 includes a setter 401, an analyzer402, a converter 403, and a superimposer 404.

The setter 401 sets process data represented in N dimensions from thedigital video signal Vdg1 as input data, sets M units of process data asan analysis unit, and generates at least one data group composed of Munits of process data. The setter 401 supplies at least one data groupto the analyzer 402 and the converter 403.

If the setter 401 generates information required for the decoder 54 ofFIG. 24 to generate conversion information (hereinafter referred to asconversion information generating information) to be discussed later,the conversion information generating information is supplied to thesuperimposer 404 as a digital signal Vb as necessary. If the setter 401generates or uses information required for the decoder 54 of FIG. 24 togenerate other information for use in decoding (hereinafter referred toas decode information generating information), the decode informationgenerating information is supplied to the superimposer 404 as a digitalsignal Vb.

In the encoder 52 of FIG. 3, the setter 401 includes the process areasegmentor 82 and the vectorizer 83. More specifically, in the encoder 52of FIG. 3, a N-dimensional process vector generated by the vectorizer 83is used as the process data. M process vectors generated from oneprocess area are used as an analysis unit. In other words, the processarea, into which the process area segmentor 82 segments the digitalvideo signal Vdg1, is used as an analysis unit.

The analyzer 402 of FIG. 22 sets each of at least one data groupsupplied from the setter 401 as a data group to be processed, thenanalyzes the data group to be processed, then generates, on a per datagroup, conversion information for converting an expression format of thedata group to be processed, and then supplies the generated conversioninformation to the converter 403.

The conversion information or the conversion information generatinginformation responsive thereto is supplied from the analyzer 402 to thesuperimposer 404 as the digital signal Vb. If the decode informationgenerating information is generated or used by the analyzer 402, thedecode information generating information is supplied from the analyzer402 to the superimposer 404 as the digital signal Vb as necessary.

In the encoder 52 of FIG. 3, the analyzer 402 includes the orthogonaltransform basis generator 84. More specifically, in the encoder 52 ofFIG. 3, the orthogonal transform basis (the first through N-th maincomponents) on a per process area basis generated by the orthogonaltransform basis generator 84 is adopted as the conversion information.In the encoder 52 of FIG. 3, the digital signal Vcdp output from theorthogonal transform basis generator 84 is adopted as one of digitalsignals Vb of FIG. 22 as the conversion information itself.

The converter 403 of FIG. 22 converts the expression format of each ofthe M units of process data forming the data group to be processed, ineach of the data groups supplied from the setter 401, using theconversion information of the data group to be processed, out of theconversion information supplied from the analyzer 402. The converter 403supplies at least one data group in the converted expression format tothe superimposer 404 as the digital signal Va.

The conversion information shows or defines the relationship between afirst expression format still unconverted by the converter 403 and asecond expression format converted by the converter 403.

In addition to an axis conversion, the conversion of the expressionformation may or may not include an encoding process (such asquantization) in accordance with a predetermined encoding method. In thecase of the axis conversion, the encoder 52 can be part of a dataconverter converting the expression format of data. In the case of theencoding process, the converter 403 encodes at least one data group inthe converted expression format, and supplies the resulting signal asthe digital signal Va to the superimposer 404.

In the encoder 52 of FIG. 3, the converter 403 includes the orthogonaltransform encoder 85. More specifically, in the encoder 52 of FIG. 3,the digital signal Vcdq output from the orthogonal transform encoder 85is used as the digital signal Va of FIG. 22.

The superimposer 404 superimposes the digital signal Vb supplied from atleast one of the setter 401 and the analyzer 402 (at least one of theconversion information, the conversion information generatinginformation and the decode information generating information) on thedigital signal Va supplied from the converter 403, and supplies theresulting digital signal to the recorder 53 and the decoder 54 of FIG. 2as the encoded digital video signal Vcd.

For example, in the encoder 52 of FIG. 3, the superimposer 404 includesthe superimposer 86.

The functional structure of the encoder 52 of FIG. 2 has been discussedwith reference to FIG. 22.

The encoding process of the encoder 52 having the functional structureof FIG. 22 is described below with reference to a flowchart of FIG. 23.

In step S201, the setter 401 inputs one frame of digital video signalVdg1.

In step S202, the setter 401 sets process data and analysis unit fromthe one frame of digital video signal Vdg1. When the one frame of aplurality units of process data is divided by analysis unit, and atleast one data group formed of M units of process data, namely, at leastone data group equal to one frame is supplied from the setter 401 to theanalyzer 402 and the converter 403, processing proceeds to step S203.

In step S203, the analyzer 402 generates one frame of conversioninformation on a per analysis unit basis. More specifically, theanalyzer 402 generates the conversion information of each of at leastone data group equal to one frame. When one frame of conversioninformation per analysis unit is supplied from the analyzer 402 to theconverter 403, processing proceeds to step S204.

In step S204, the converter 403 converts the expression format of oneframe of digital video signal Vdg1 on a per analysis unit basis usingthe one frame of conversion information per analysis unit. The converter403 converts the expression format of the data group to be processed, ineach of at least one data group equal to one frame, using the conversioninformation of the data group to be processed. As a result of theprocess in step S204, one frame of digital signal Va is obtained. Whenthe digital signal Va is supplied from the converter 403 to thesuperimposer 404, processing proceeds to step S205.

In step S205, the superimposer 404 superimposes the digital signal Vbsupplied from at least one of the setter 401 and the analyzer 402 ontoone frame of digital signal Va supplied from the converter 403, therebygenerating the encoded digital video signal Vcd.

In step S206, the superimposer 404 outputs the encoded digital videosignal Vcd.

In step S207, the encoder 52 determines whether all frames to beprocessed have been processed.

If it is determined that all frames have not been processed yet, namely,if the answer to the determination in step S207 is no, processingreturns to step S201 to repeat step S201 and subsequent steps. Morespecifically, a next one frame of digital video signal Vdg1 is input instep S201, and the encoding process is repeated in steps S202 throughS205. As a result, a next one frame of encoded digital video signal Vcdis obtained, and then output in step S206.

Steps S201 through S207 are looped to process all fames. When last frameof encoded digital video signal Vcd is output, the answer to thedetermination in step S207 is yes, and the encoding process of FIG. 23is completed.

The encoding process of the encoder 52 having the functional structureof FIG. 22 has been discussed with reference to FIG. 23.

The functional structure of the decoder 54 corresponding to the encoder52 having the function structure of FIG. 22 is described below withreference to FIGS. 24 and 25.

As shown in FIG. 24, the decoder 54 includes a data decomposer 411through a decoded video generator 414. As will be described later, theanalyzer 412 may be omitted as appropriate.

The data decomposer 411 receives the encoded digital video signal Vcdsupplied from the encoder 52 having the functional structure of FIG. 22.

The data decomposer 411 decomposes the encoded digital video signal Vcdinto the digital signal Va output from the converter 403 of FIG. 22 andthe digital signal Vb output from at least one of the setter 401 and theanalyzer 402 of FIG. 22.

As described above, the digital signal Vb contains at least one of theconversion information, the conversion information generatinginformation responsive to the conversion information, and the decodeinformation generating information. If the digital signal Vb containsthe conversion information, the data decomposer 411 supplies theconversion information to the inverse-converter 413. If the digitalsignal Vb contains the conversion information generating information,the data decomposer 411 supplies the conversion information generatinginformation to the analyzer 412. If the digital signal Vb contains thedecode information generating information, the data decomposer 411supplies the decode information generating information to one of theanalyzer 412 through the decoded video generator 414.

In the decoder 54 of FIG. 14, the data decomposer 411 includes the datadecomposer 102.

Upon receipt of the conversion information generating information as thedigital signal Vb from the data decomposer 411, the analyzer 412generates the conversion information on a per analysis unit (theconversion information corresponding to the output of the analyzer 402of FIG. 22) using the conversion information generating information, andsupplies the conversion information to the inverse-converter 413. Theanalyzer 412 generates the conversion information for each of at leastone data group, and supplies the conversion information to theinverse-converter 413.

Since the digital signal Vb contains no conversion informationgenerating information in the decoder 54 of FIG. 14, in other words, thedigital signal Vb includes the digital signal Vcdp, which is theconversion information itself, the analyzer 412 is omitted.

The inverse-converter 413 converts the digital signal Va supplied fromthe data decomposer 411 back to the original format thereof using theconversion information per analysis unit supplied from the datadecomposer 411 as the digital signal Vb or the conversion informationper analysis unit supplied from the analyzer 412. More specifically, theinverse-converter 413 converts the data group to be processed back tothe original expression format in each of the process data in theconverted expression format (at least one data group), using theconversion information of the data group to be processed. Theinverse-converter 413 supplies, to the decoded video generator 414, theprocess data per analysis unit in the original expression format (atleast one data group).

In addition to the expression format conversion through theabove-described axis conversion, the expression format conversion may ormay not include the decoding process (inverse quantization)corresponding to the encoding method used by the converter 403 of FIG.22. If the axis conversion is used, the decoder 54 is interpreted asbeing part or whole of a data inverse converting apparatus for inverseconverting the expression format of data. If the inverse quantizationprocess is used, the inverse-converter 413 decodes the digital signal Vasupplied from the data decomposer 411 and causes the resulting signal torevert back to the original expression format.

In the decoder 54 of FIG. 14, for example, the inverse-converter 413includes the inverse orthogonal transform decoder 103.

Using the process data per analysis unit (at least one data group)caused to revert back to the original expression format by theinverse-converter 413, the decoded video generator 414 generates thedigital video signal Vdg2 that is a decoded signal of the encodeddigital video signal Vcd input to the data decomposer 411, and suppliesthe digital video signal Vdg2 to the D/A converter 55 of FIG. 2.

In the decoder 54 of FIG. 14, the decoded video generator 414 includesthe block decomposer 104.

If the digital signal Vb, which is the decode information generatinginformation, is supplied, the analyzer 412 through the decoded videogenerator 414 execute the above-described variety of processes asnecessary using the decode information generating information.

The decoder 54 having the functional structure of FIG. 24 has beendiscussed. The decoding process of the decoder 54 having the functionalstructure of FIG. 24 is described below with reference to a flowchart ofFIG. 25.

In step S221, the data decomposer 411 receives one frame of encodeddigital video signal Vcd.

In step S222, the data decomposer 411 decomposes the one frame ofencoded digital video signal Vcd into one frame of digital signal Va andone frame of digital signal Vb.

In step S223, the data decomposer 411 determines whether the conversioninformation has been decomposed.

If the digital signal Vb decomposed from the encoded digital videosignal Vcd in step S222 contains one frame of conversion information peranalysis unit, the data decomposer 411 proceeds to step S225 withoutperforming the process in step S224 after determining in step S223 theconversion information has been decomposed. The digital signal Vb, whichis one frame of conversion information per analysis unit, is thensupplied from the data decomposer 411 to the inverse-converter 413.

In contrast, if the digital signal Vb decomposed from the encodeddigital video signal Vcd in step S222 contains no conversion informationbut contains one frame of conversion information generating informationper analysis unit, the data decomposer 411 determines in step S223 thatthe conversion information has not been decomposed. The digital signalVb, which one frame of conversion information generating information peranalysis unit, is supplied from the data decomposer 411 to the analyzer412. Processing proceeds to step S224.

In step S224, the analyzer 412 generates one frame of conversioninformation per analysis unit using one frame of conversion informationgenerating information per analysis unit. When the one frame ofconversion information per analysis unit is supplied from the analyzer412 to the inverse-converter 413, processing proceeds to step S225.

In step S225, the inverse-converter 413 causes one frame of encodeddigital video signal Vcd to revert back to the original expressionformat thereof on a per analysis unit basis using the one frame ofconversion information per analysis unit supplied from one of the datadecomposer 411 and the analyzer 412. In other words, the process in stepS225 is interpreted as an inverse process of the conversion process instep S204 of FIG. 23.

The reversion of the expression format of the encoded digital videosignal Vcd to the original format on a per analysis unit basis resultsin the process data per analysis unit in the original expression format(at least one data group). Through the process in step S225, the processdata per analysis unit in the original expression format (at least onedata group) is supplied from the inverse-converter 413 to the decodedvideo generator 414. Processing proceeds to step S226.

In step S226, the decoded video generator 414 generates, from theprocess data per analysis unit in the original expression format (atleast one data group), one frame of digital video signal Vdg2, which isa decoded signal of one frame of encoded digital video signal Vcd inputin step S221.

In step S227, the decoded video generator 414 outputs the one frame ofdigital video signal Vdg2.

In step S228, the decoder 54 determines whether all frames to beprocessed have been processed.

If it is determined that all frames have not been processed yet, i.e.,if the answer to the determination in step S228 is no, processingreturns to step S221 to repeat step S221 and subsequent steps. Morespecifically, a next one frame of encoded digital video signal Vcd isinput in step S221, and the above-described decoding process isperformed in steps S222 through S226. As a result, a next frame ofdigital video signal Vdg2 is obtained and output in step S227.

Steps S221 through S228 are looped to process all frames. When lastframe of digital video signal Vdg2 is output, the answer to thedetermination in step S228 becomes yes. The decoding process of FIG. 25is completed.

The decoding process of the decoder 54 having the functional structureof FIG. 24 has been discussed with reference to FIG. 25.

The encoder 52 of FIG. 2 and the decoder 54 corresponding thereto havebeen discussed in detail with reference to FIGS. 3 through 25.

The video processing system of embodiments of the present invention isnot limited to the system of FIG. 2. The present invention may beimplemented in a variety of embodiments. The present invention is notlimited to any particular arrangement as long as the arrangementincludes the encoder 52 having the functional structure of FIG. 22 andthe decoder 54 having the functional structure of FIG. 24. For example,the video processing system of one embodiment of the present inventionmay be arranged as shown in FIG. 26.

FIG. 26 illustrates the video processing system of one embodiment of thepresent invention.

In the video processing system of FIG. 26, elements identical to thosein the video processing system of FIG. 2 are designated with the samereference numerals and the discussion thereof is omitted as appropriate.

In comparison of the system of FIG. 26 with the system of FIG. 2, theencoding section 41 of FIG. 26 includes further an analog distortionadder 451 in addition to the encoding section 41 of FIG. 2.

The analog distortion adder 451 positively generates an analog signal tothe analog video signal Van1 output from the reproducing apparatus 1 asthe name thereof implies. The analog distortion adder 451 then suppliesthe A/D converter 51 with the analog video signal Van1 with the analognoise forcibly added thereto.

The layout position of the analog distortion adder 451 is not limited tothat of FIG. 26. For example, the analog distortion adder 451 may bearranged behind the D/A converter 55 in the decoding section 42, orbehind the D/A converter 12.

The remaining structure of the video processing system of FIG. 26 isidentical to that of the video processing system of FIG. 2. The videoprocessing system of FIG. 26 is generally identical in operation to thevideo processing system of FIG. 2 except that the analog distortionadder 451 forces the analog distortion to be added to the analog videosignal Van1, and the discussion of the operation of the video processingsystem of FIG. 26 is thus omitted herein.

The above-referenced series of process steps may partly or entirely beperformed in hardware or software.

In the video processing systems of FIG. 2 and FIG. 26, part (forexample, the encoder 52 or the decoder 54) or whole of each of theencoding section 41 and the decoding section 42 is implemented by acomputer having a structure of FIG. 27.

As shown in FIG. 27, a central processing unit (CPU) 501 performs avariety of processes in accordance with a program stored in a read-onlymemory (ROM) 502, and a program loaded from a recording unit 508 to arandom-access memory (RAM) 503. The RAM 503 also stores data requiredfor the CPU 501 to perform a variety of programs.

The CPU 501, the ROM 502, and the RAM 503 are mutually connected to eachother via a bus 504. The bus 504 also connects to an input and outputinterface 505.

The input and output interface 505 connects to an input unit 505including a keyboard and a mouse, an output unit 507 such as a display,a recording unit 508 such as a hard disk, and a communication unit 509including a modem and a terminal adaptor. The communication unit 509performs a communication process to communicate with another apparatusvia networks including the Internet.

The input and output interface 505 connects to a drive 510, asnecessary. The drive 510 is loaded with a removable recording medium 511such as a magnetic disk, an optical disk, a magneto-optical disk, or asemiconductor memory. A computer program read from the removablerecording medium 511 is installed onto the recording unit 508, asnecessary.

To perform the series of process steps in software, the computer programforming the software is installed via the network or from the recordingmedium onto a computer built in dedicated hardware or a general-purposepersonal computer that can perform a variety of functions when a varietyof programs are installed thereon.

As shown in FIG. 27, the recording medium having stored the programincludes the removable medium 511 distributed to a user separate fromthe apparatus to provide the user with the program. The recording mediainclude, for example, a magnetic disk (including a floppy disk), anoptical disk (such as compact disk read-only memory (CD-ROM)), ordigital versatile disk (DVD)), a magneto-optical disk (such as mini-disk(MD®), and a semiconductor memory. The recording media also include theROM 502, and a hard disk loaded on the recording unit 508′, each havingstored the program.

The process steps describing the program stored on the recording mediummay be performed in the time-series order sequence as previously stated.Alternatively, the process steps may be performed in parallel orseparately.

In the context of this specification, the system refers to an entiresystem including a plurality of apparatuses, and processing units.

In the previous discussion, an object to be encoded or decoded is thevideo signal. Alternatively, the object to be encoded or decoded may beany other signal.

In the previous discussion, the frame is the unit handled in theabove-described variety of processes. Alternatively, the unit in theprocesses may be a field. If the units in the processes, such as theframe and the field, are referred to as an access unit, the unit ofprocess is the access unit in the previous discussion.

In accordance with the embodiments of the present invention, the videodata is encoded and decoded. In a manner free from occurrence ofundisplayed image, and an increase in circuit scale, unauthorizedcopying using the analog video signal is discouraged by significantlydegrading the video data in the second and subsequent cycles of encodingand decoding.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

1. A data converting apparatus, comprising: segmenting means for setting a predetermined access unit, as an access unit to be processed, out of input data containing at least one access unit containing a plurality of data components per pixel, and for segmenting the predetermined access unit into at least one block; analyzing means for generating, on a per analysis block basis, a basis for converting an expression format of each of the plurality of data components by respectively setting, as at least one analysis block, an at least one segmented block, and for performing a main component analysis on the plurality of data components on a per at least one analysis block basis, wherein the main component analysis comprises averaging position vectors and calculating a difference vector and mean value therefrom; converting means for converting the expression format of each of the plurality of data components per pixel forming the block to be processed, by successively setting, as at least one block to be processed, the at least one segmented block, and by using a predetermined one of at least one basis generated by the analyzing means; and vectorizing means for generating an N-dimensional first vector having values of N data components (N is an integer equal to 1 or larger) as element values thereof per pixel, on every M pixels (M is an integer equal to 1 or larger) in the block to be processed, by successively setting, as the block to be processed on a one-by-one basis, the at least one segmented block, wherein the analyzing means generates the basis of the block to be analyzed by performing the main component analysis on the M first vectors generated by the vectorizing means when the block to be analyzed becomes the block to be processed.
 2. The data converting apparatus according to claim 1, further comprising analog distortion generating means for generating an analog distortion in the input data.
 3. The data converting apparatus according to claim 1, wherein the converting means encodes, on a per predetermined unit basis, a data group containing the plurality of data components per pixel in the converted expression format in the block to be processed.
 4. The data converting apparatus according to claim 1, wherein the converting means respectively converts the M first vectors of the block to be processed, from among the first vectors represented by a first coordinate system having each of the N data components as an axis thereof, into M second vectors represented by a second coordinate system having, as an axis, the basis generated by the analyzing means when the block to be processed becomes the block to be analyzed.
 5. The data converting apparatus according to claim 4, wherein the converting means encodes, on a per predetermined unit basis, a data group containing the M second vectors in the block to be processed.
 6. The data converting apparatus according to claim 1, wherein the plurality of data components includes first pixel data representing a red luminance level of a corresponding pixel, second pixel data representing a green luminance level of the corresponding pixel, and a third luminance level representing a blue luminance level of the corresponding pixel.
 7. A data converting method for converting at least part of an expression format of input data containing at least one access unit containing a plurality of data components per pixel, the method comprising: setting a predetermined access unit of the input data, as an access unit to be processed, and segmenting the predetermined access unit into at least one block; generating, on a per analysis block basis, a basis for converting an expression format of each of the plurality of data components by respectively setting, as at least one analysis block, the at least one segmented block, and performing a main component analysis on the plurality of data components on a per at least one analysis block basis, wherein the main component analysis comprises averaging position vectors and calculating a difference vector and mean value therefrom; converting the expression format of each of the plurality of data components per pixel forming the block to be processed by successively setting, as at least one block to be processed, the at least one segmented block, and by using a predetermined one of at least one basis generated in the analyzing step; and vectorizing by generating an N-dimensional first vector having values of N data components (N is an integer equal to 1 or larger) as element values thereof per pixel, on every M pixels (M is an integer equal to 1 or larger) in the block to be processed, by successively setting, as the block to be processed on a one-by-one basis, the at least one segmented block, wherein the generating the basis for converting generates the basis of the block to be analyzed by performing the main component analysis on the M first vectors generated by the vectorizing when the block to be analyzed becomes the block to be processed.
 8. A non-transitory recording medium storing a computer program for causing a computer to perform a data converting method of converting at least part of an expression format of input data containing at least one access unit containing a plurality of data components per pixel, the data converting method comprising: setting a predetermined access unit of the input data, as an access unit to be processed, and segmenting the predetermined access unit into at least one block; generating, on a per analysis block basis, a basis for converting an expression format of each of the plurality of data components by respectively setting, as at least one analysis block, the at least one segmented block, and performing a main component analysis on the plurality of data components on a per at least one analysis block basis, wherein the main component analysis comprises averaging position vectors and calculating a difference vector and mean value therefrom; converting the expression format of each of the plurality of data components per pixel forming the block to be processed by successively setting, as at least one block to be processed, the at least one segmented block, and by using a predetermined one of at least one basis generated in the analyzing step; and vectorizing by generating an N-dimensional first vector having values of N data components (N is an integer equal to 1 or larger) as element values thereof per pixel, on every M pixels (M is an integer equal to 1 or larger) in the block to be processed, by successively setting, as the block to be processed on a one-by-one basis, the at least one segmented block, wherein the generating the basis for converting generates the basis of the block to be analyzed by performing the main component analysis on the M first vectors generated by the vectorizing when the block to be analyzed becomes the block to be processed.
 9. A data inverse converting apparatus in a system in which a predetermined first access unit is set as an access unit to be processed out of original data containing at least one first access unit containing a plurality of data components per pixel, and the first access unit to be processed is segmented into at least one block; the at least one segmented block is successively set as at least one analysis block, a main component analysis is performed on each of the plurality of data components on a per at least one analysis block basis, a basis for converting an expression format of each of the plurality of data components is generated on a per analysis block basis, wherein the main component analysis comprises averaging position vectors and calculating a difference vector and mean value therefrom; and the at least one segmented block is successively set as a block to be processed, the expression format of each of the plurality of data components per pixel forming the block to be processed is converted using a predetermined one of at least one generated basis, a second access unit containing the plurality of data components per pixel in the converted expression format is generated, and the data inverse converting apparatus receives input data containing the basis being input as part of the input data, the basis being used to generate the second access unit; the data inverse converting apparatus comprises: separating means for separating the input data into the second access unit and the basis; and inverse converting means for inverse converting, using the separated basis, the expression format of the plurality of data components per pixel forming the separated second access unit.
 10. A data inverse converting method of a data inverse converting apparatus in a system in which a predetermined first access unit is set as an access unit to be processed out of original data containing at least one first access unit containing a plurality of data components per pixel, and the first access unit to be processed is segmented into at least one block; the at least one segmented block is successively set as at least one analysis block, a main component analysis is performed on each of the plurality of data components on a per at least one analysis block basis, and a basis for converting an expression format of each of the plurality of data components is generated on a per analysis block basis, wherein the main component analysis comprises averaging position vectors and calculating a difference vector and mean value therefrom; and the at least one segmented block is successively set as a block to be processed, the expression format of each of the plurality of data components per pixel forming the block to be processed is converted using a predetermined one of at least one generated basis, a second access unit containing the plurality of data components per pixel in the converted expression format is generated, and the data inverse converting apparatus receives input data containing the basis being input as part of the input data, the basis being used to generate the second access unit; the data inverse converting method comprises: separating the input data into the second access unit and the basis; and inverse converting, using the separated basis, the expression format of the plurality of data components per pixel forming the separated second access unit.
 11. A non-transitory recording medium storing a computer program for causing a computer to perform a data inverse converting method of a data inverse converting apparatus in a system in which a predetermined first access unit is set as an access unit to be processed out of original data containing at least one first access unit containing a plurality of data components per pixel, and the first access unit to be processed is segmented into at least one block; the at least one segmented block is successively set as at least one analysis block, a main component analysis is performed on each of the plurality of data components on a per at least one analysis block basis, and a basis for converting an expression format of each of the plurality of data components is generated on a per analysis block basis, wherein the main component analysis comprises averaging position vectors and calculating a difference vector and mean value therefrom; and the at least one segmented block is successively set as a block to be processed, the expression format of each of the plurality of data components per pixel forming the block to be processed is converted using a predetermined one of at least one generated basis, a second access unit containing the plurality of data components per pixel in the converted expression format is generated, and the data inverse converting apparatus receives input data containing the basis being input as part of the input data, the basis being used to generate the second access unit; the data inverse converting method comprises: separating the input data into the second access unit and the basis; and inverse converting, using the separated basis, the expression format of the plurality of data components per pixel forming the separated second access unit.
 12. A data inverse converting apparatus in a system in which a predetermined access unit is set as an access unit to be processed out of original data containing at least one access unit containing a plurality of data components per pixel, and the access unit to be processed is segmented into at least one block; the at least one segmented block is successively set as at least one analysis block, a main component analysis is performed on each of the plurality of data components on a per at least one analysis block basis, and a basis for converting an expression format of each of the plurality of data components is generated on a per analysis block basis, wherein the main component analysis comprises averaging position vectors and calculating a difference vector and mean value therefrom; and the at least one segmented block is successively set as a block to be processed, the expression format of each of the plurality of data components per pixel forming the block to be processed is converted using a predetermined one of at least one generated basis, a data group containing the plurality of data components per pixel in the converted expression format is encoded, at least one unit of encoded data respectively corresponding to the at least one block is obtained, and the inverse converting apparatus receives input data containing the basis being input as part of the input data, the basis being used to generate and being associated with the at least one unit of encoded data; the data inverse converting apparatus comprises: separating means for separating the input data into the at least one unit of encoded data and the basis associated with the at least one unit of encoded data; and inverse converting means for successively setting the at least one separated unit of encoded data as a unit of encoded data to be processed one by one, for decoding the unit of encoded data to be processed, and for inverse converting, using the basis associated with the unit of encoded data to be processed from among the bases separated from the input data, the expression format of the plurality of data components per pixel forming the data group obtained as a result of decoding.
 13. The data inverse converting apparatus according to claim 12, wherein the original data contains an analog distortion.
 14. The data inverse converting apparatus according to claim 12, wherein: the at least one block is successively set one by one as a unit of block to be processed, and N-dimensional first vectors having values of N data components (N being an integer equal to 2 or larger) as component values per pixel are generated every M pixels (M being an integer equal to 1 or larger) corresponding to the block to be processed; the basis of the block to be analyzed is generated when the main component analysis is performed on the M first vectors that are generated after the block to be analyzed becomes the block to be processed; and each of the M first vectors of the block to be processed, from among the first vectors represented by a first coordinate system having as an axis each of the N data components, is converted into each of M second vectors represented by a second coordinate system having as an axis thereof the basis generated when the block to be processed becomes the block to be analyzed, the data group containing the M second vectors is encoded on a per predetermined unit basis, and as a result, at least one unit of encoded data corresponding to the at least one block is obtained; the input data containing the basis being input as part of the input data is input, the basis being used to generate and being associated with the at least one unit of encoded data; and the inverse converting means decodes one of encoded data to be processed, and respectively inverse converts the M second vectors forming the data group obtained as a result of decoding the one of encoded data to be processed, into the M first vectors using the basis associated with the one unit of encoded data to be processed.
 15. The data inverse converting apparatus according to claim 12, wherein the plurality of data components includes first pixel data representing a red luminance level of a corresponding pixel, second pixel data representing a green luminance level of the corresponding pixel, and a third luminance level representing a blue luminance level of the corresponding pixel.
 16. A data inverse converting method of a data inverse converting apparatus in a system in which a predetermined access unit is set as an access unit to be processed out of original data containing at least one access unit containing a plurality of data components per pixel, and the access unit to be processed is segmented into at least one block; the at least one segmented block is successively set as at least one analysis block, a main component analysis is performed on each of the plurality of data components on a per at least one analysis block basis, and a basis for converting an expression format of each of the plurality of data components is generated on a per analysis block basis, wherein the main component analysis comprises averaging position vectors and calculating a difference vector and mean value therefrom; and the at least one segmented block is successively set as a block to be processed, the expression format of each of the plurality of data components per pixel forming the block to be processed is converted using a predetermined one of at least one generated basis, a data group containing the plurality of data components per pixel in the converted expression format is encoded, at least one unit of encoded data respectively corresponding to the at least one block is obtained, and the inverse converting apparatus receives input data containing a basis being input as part of the input data, the basis being used to generate and being associated with the at least one unit of encoded data; the data inverse converting method comprises: separating the input data into the at least one unit of encoded data and the basis associated with the at least one unit of encoded data; and successively setting the at least one separated unit of encoded data as a unit of encoded data to be processed one by one, decoding the unit of encoded data to be processed, and inverse converting, using the basis associated with the unit of encoded data to be processed from among the bases separated from the input data, the expression format of the plurality of data components per pixel forming the data group obtained as a result of decoding.
 17. A non-transitory recording medium storing a computer program for causing a computer to perform a data inverse converting method of a data inverse converting apparatus in a system in which a predetermined access unit is set as an access unit to be processed out of original data containing at least one access unit containing a plurality of data components per pixel, and the access unit to be processed is segmented into at least one block; the at least one segmented block is successively set as at least one analysis block, a main component analysis is performed on each of the plurality of data components on a per at least one analysis block basis, and a basis for converting an expression format of each of the plurality of data components is generated on a per analysis block basis, wherein the main component analysis comprises averaging position vectors and calculating a difference vector and mean value therefrom; and the at least one segmented block is successively set as a block to be processed, the expression format of each of the plurality of data components per pixel forming the block to be processed is converted using a predetermined one of at least one generated basis, a data group containing the plurality of data components per pixel in the converted expression format is encoded, at least one unit of encoded data respectively corresponding to the at least one block is obtained, and the inverse converting apparatus receives input data containing the basis being input as part of the input data, the basis being used to generate and being associated with the at least one unit of encoded data; the data inverse converting method comprises: separating the input data into the at least one unit of encoded data and the basis associated with the at least one unit of encoded data; and successively setting the at least one separated unit of encoded data as a unit of encoded data to be processed one by one, decoding the unit of encoded data to be processed, and inverse converting, using the basis associated with the unit of encoded data to be processed from among the bases separated from the input data, the expression format of the plurality of data components per pixel forming the data group obtained as a result of decoding.
 18. A data converting apparatus, comprising: a segmentor operable to set a predetermined access unit, as an access unit to be processed, out of input data containing at least one access unit containing a plurality of data components per pixel, and to segment the predetermined access unit into at least one block; an analyzer operable to generate, on a per analysis block basis, a basis for converting an expression format of each of the plurality of data components by respectively setting, as at least one analysis block, the at least one segmented block, and to perform a main component analysis on the plurality of data components on a per at least one analysis block basis, wherein the main component analysis comprises averaging position vectors and calculating a difference vector and mean value therefrom; a converter operable to convert the expression format of each of the plurality of data components per pixel forming the block to be processed, by successively setting, as at least one block to be processed, the at least one segmented block, and by using a predetermined one of at least one basis generated by the analyzer; and a vectorizer to generate an N-dimensional first vector having values of N data components (N is an integer equal to 1 or larger) as element values thereof per pixel, on every M pixels (M is an integer equal to 1 or larger) in the block to be processed, by successively setting, as the block to be processed on a one-by-one basis, the at least one segmented block, wherein the analyzer generates the basis of the block to be analyzed by performing the main component analysis on the M first vectors generated by the vectorizer when the block to be analyzed becomes the block to be processed.
 19. A data inverse converting apparatus in a system in which a predetermined first access unit is set as an access unit to be processed out of original data containing at least one first access unit containing a plurality of data components per pixel, and the first access unit to be processed is segmented into at least one block; the at least one segmented block is successively set as at least one analysis block, a main component analysis is performed on each of the plurality of data components on a per at least one analysis block basis, and a basis for converting an expression format of each of the plurality of data components is generated on a per analysis block basis, wherein the main component analysis comprises averaging position vectors and calculating a difference vector and mean value therefrom; and the at least one segmented block is successively set as a block to be processed, the expression format of each of the plurality of data components per pixel forming the block to be processed is converted using a predetermined one of at least one generated basis, a second access unit containing the plurality of data components per pixel in the converted expression format is generated, and the data inverse converting apparatus receives input data containing the basis being input as part of the input data, the basis being used to generate the second access unit; the data inverse converting apparatus comprises: a separator operable to separate the input data into the second access unit and the basis; and an inverter operable to inverse convert, using the separated basis, the expression format of the plurality of data components per pixel forming the separated second access unit.
 20. A data inverse converting apparatus in a system in which a predetermined access unit is set as an access unit to be processed out of original data containing at least one access unit containing a plurality of data components per pixel, and the access unit to be processed is segmented into at least one block; the at least one segmented block is successively set as at least one analysis block, a main component analysis is performed on each of the plurality of data components on a per at least one analysis block basis, and a basis for converting an expression format of each of the plurality of data components is generated on a per analysis block basis, wherein the main component analysis comprises averaging position vectors and calculating a difference vector and mean value therefrom; and the at least one segmented block is successively set as a block to be processed, the expression format of each of the plurality of data components per pixel forming the block to be processed is converted using a predetermined one of at least one generated basis, a data group containing the plurality of data components per pixel in the converted expression format is encoded, at least one unit of encoded data respectively corresponding to the at least one block is obtained, and the inverse converting apparatus receives input data containing the basis being input as part of the input data, the basis being used to generate and being associated with the at least one unit of encoded data; the data inverse converting apparatus comprises: a separator operable to separate the input data into the at least one unit of encoded data and the basis associated with the at least one unit of encoded data; and an inverter operable to successively set the at least one separated unit of encoded data as a unit of encoded data to be processed one by one, to decode the unit of encoded data to be processed, and to inverse convert, using the basis associated with the unit of encoded data to be processed from among the bases separated from the input data, the expression format of the plurality of data components per pixel forming the data group obtained as a result of decoding. 